

InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
151. |
What number should be added to \(\frac{-5}{11}\) so as to get \(\frac{26}{33}\) ? |
Answer» Suppose x be the rational number to be added to \(\frac{-5}{11}\) to get \(\frac{26}{33}\) Then, \(\frac{-5}{11}\)+x = \(\frac{26}{33}\) x = \(\frac{26}{33}\)+\(\frac{5}{11}\) x = \(\frac{26\times 1+5\times 3}{33}\) x = \(\frac{26+15}{33}\) x = \(\frac{41}{33}\) Therefore, The required number x = \(\frac{41}{33}\) |
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152. |
What number should be added to (-5/7) to get (-2/3)? |
Answer» Given (-5/7) Let the required number be x x + (-5/7) = (-2/3) x = (-2/3) – (-5/7) x = (-2/3) + (5/7) LCM of 3 and 7 is 21 Consider (-2/3) = (-2/3) × (7/7) = (-14/21) Again (5/7) = (5/7) × (3/3) = (15/21) On substituting x = (-14/21) + (15/21) x = (-14 + 15)/21 x = (1/21) |
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153. |
What number should be subtracted from \(\frac{-2}{3}\) to get \(\frac{-1}{6}?\) |
Answer» Let the number = x Now, According to question, \(\frac{-2}{3}-\) x \(=\frac{-1}{6}\) \(\Rightarrow\) x = \(\frac{-2}{3}-(\frac{-1}{6})\) \(\Rightarrow\) x \(=\frac{-4-(-1)}{6}\) \(\Rightarrow\) x \(\frac{-4+1}{6}\) \(\Rightarrow\) x \(=\frac{-3}{6}\) In lowest terms, x \(=\frac{-3÷3}{6÷3}= \frac{-1}{2}\) Therefore, \(\frac{-1}{2}\) should be subtracted from \(\frac{-2}{3}\) so as to get \(\frac{-1}{6}\) |
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154. |
What number should be subtracted from (-5/3) to get (5/6)? |
Answer» Given (-5/3) Let the required number be x (-5/3) – x = (5/6) – x = (5/6) – (-5/3) – x = (5/6) + (5/3) Consider (5/3) = (5/3) × (2/2) = (10/6) On substituting – x = (5/6) + (10/6) – x = (15/6) x = (-15/6) |
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155. |
Using suitable rearrangement and find the sum-5 + (7/10) + (3/7) + (-3) + (5/45) + (-4/5) |
Answer» = -5 + (-3) + (7/10) + (-4/5) + (3/7) + (5/14) = 8 + [(7-8)/10] + [(6 + 5)/14] = – 8 – (1/10) + (11/14) LCM of 1, 10 and 14 is 70 = (-560 – 7 + 55)/70 = -512/70 = – 256/35 |
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156. |
Using suitable rearrangement and find the sum(4/7) + (-4/9) + (3/7) + (-13/9) |
Answer» First rearrange the rational numbers and add the numbers with same denominator. = (4/7) + (3/7) – (4/9) – (13/9) = ((4 + 3)/7) – ((4 + 13)/9) = (7/7) – (17/9) = 1 – (17/9) = (9 – 17)/9 = -8/9 |
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157. |
Subtracti) 3/4 from 1/3ii) \(\frac{-32}{13}\) from 2iii) -7 from -4/7 |
Answer» i) \(\)3/4 from 1/3 \(\Rightarrow \frac13\,-\,\frac34=\frac{4\,-\,9}{12} = \frac{-5}{12}\) ii) -32/13 from 2 \(\Rightarrow 2\,-\,(\frac{-32}{13})\) \(\Rightarrow 2\,+\,\frac{32}{13}=\frac{26\,+\,32}{13}=\frac{58}{13}\) iii) -7 from -4/7 \(\Rightarrow \frac{-4}7\,-\,(-7)=\frac{-4}7\,+\,7\) \(\frac{-4\,+\,49}{7}=\frac{45}7\) |
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158. |
Subtract : (-32/13) from (-6/5) |
Answer» (-32/13) from (-6/5) We have: = (-6/5) – (-32/13) = (-6/5) + (additive inverse of -32/13) = (-6/5) + (32/13) LCM of 5 and 13 is 65 Express each of the given rational numbers with the above LCM as the common denominator. Now, = [(-6×13)/ (5×13)] = (-78/65) = [(32×5)/ (13×5)] = (160/65) Then, = (-78/65) + (160/65) = (-78+160)/65 = (82/65) |
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159. |
Subtract: (i) \(\frac{-18}{11}\) from 1(ii) \(\frac{-13}{9}\) from 0(iii) \(\frac{-32}{13}\) from \(\frac{-6}{5}\) (iv) \(-7\) from \(\frac{-4}{7}\) |
Answer» (i) We can write, 1 = \(\frac{1}{1}\) Since the denominators of both the numbers are different therefore, we will take their LCM 0f 1 and 11 = 11 \(\frac{1}{1} = \frac{1\times11}{1\times11}= \frac{11}{11}\) And, \(\frac{18}{11} = \frac{-18\times1}{11\times1}= \frac{-18}{11}\) Therefore, \(1-(\frac{-18}{11})\) = \(\frac{11}{11}-(\frac{-18}{11})\) = \(\frac{11-(-18)}{11}\) = \(\frac{11+18}{11}\) = \(\frac{29}{11}\) (ii) \(0-(\frac{-13}{9})\) = \(0+\frac{13}{9}\) = \(\frac{13}{9}\) (iii) Since the denominators of both the numbers are different therefore, we will take their LCM 0f 13 and 5 = 65 \(\frac{-6}{5}= \frac{-6\times13}{5\times13}\frac{-78}{65}\) Therefore, \(\frac{-6}{5}-(\frac{-32}{13})\) = \(\frac{-78}{65}-(\frac{-160}{65})\) = \(\frac{-78-(-160)}{65}\) = \(\frac{-78+160}{65}\) = \(\frac{82}{65}\) (iv) We can write, \(-7= \frac{-7}{1}\) Since the denominators of both the numbers are different therefore, we will take their LCM 0f 1 and 7 = 7 \(\frac{-7}{1}= \frac{-7\times7}{1\times7}= \frac{-49}{7}\) And, \(\frac{-4}{7}= \frac{-4\times1}{7\times1}= \frac{-4}{7}\) Therefore, = \(\frac{-4}{7}-(-7)\) = \(\frac{-4}{7}-(\frac{-49}{7})\) = \(\frac{-4-(-49)}{7}\) = \(\frac{-4+49}{7}\) = \(\frac{45}{7}\) |
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160. |
Subtract : (-13/9) from (0) |
Answer» (-13/9) from (0) We have: = (-13/9) – (0) = (0/1) + (additive inverse of -13/9) = (0/1) + (13/9) LCM of 1 and 9 is 9 Express each of the given rational numbers with the above LCM as the common denominator. Now, = [(0×9)/ (1×9)] = (0/9) = [(13×1)/ (9×1)] = (13/9) Then, = (0/9) + (13/9) = (0+13)/9 = (13/9) |
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161. |
Fill in the blanks to make the statement true.(1/5) × [(2/7) + (3/8)] = [(1/5) × (2/7)] + _________. |
Answer» (1/5) × [(2/7) + (3/8)] = [(1/5) × (2/7)] + [(1/5) × (3/8)] ∵ From the rule of distributive law of multiplication [a × (b + c) = (a × b) + (a × c)] |
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162. |
The sum of two rational numbers is -8. If one of the numbers is \(\frac{-15}{7}\) , find the other |
Answer» It is given that, The sum of the two numbers = -8 One of the number = \(\frac{-15}{7}\) Suppose the other number is x Since, The sum is -8 Therefore, x + \(\frac{-15}{7}\) = -8 \(\frac{7x-15}{7}\) = -8 7x - 15 = -56 7x = -56 + 15 7x = -41 x = \(\frac{-41}{7}\) |
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163. |
What should be added to \(\frac{-7}{8}\) so as to get \(\frac{5}{9}\) ? |
Answer» Suppose x be the rational number to be added to \(\frac{-7}{8}\) to get \(\frac{5}{9}\) Then, \(\frac{-7}{8}\)+x = \(\frac{5}{9}\) x = \(\frac{5}{9}\)+\(\frac{7}{8}\) x = \(\frac{5\times 8+7\times 9}{72}\) x = \(\frac{40+63}{72}\) x = \(\frac{103}{72}\) Therefore, The required number x = \(\frac{103}{72}\) |
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164. |
The cost of 2 (1/3) meters of cloth is Rs.75 (1/4). Find the cost of cloth per meter. |
Answer» Given cost of 2(1/3) metres of rope = Rs. 75 (1/4) Cost of cloth per meter = 75 (1/4) ÷ 2 (1/3) = (301/4) ÷ (7/3) = (301/4) × (3/7) = (129/4) = Rs 32 (1/4) |
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165. |
Consider the following collection of numbers 1, 1/2 , -2, 0.5, 4\(\frac12\) , -33/7, 0, 4/7, 0.\(\bar3\), 22, -5,2/19 , 0.125. Write these numbers under the appropriate category. [A number can be written in more than one group] |
Answer» i) Natural numbers 1, 22 ii) Whole numbers 0, 1, 22 iii) Integers 0, 1, 22, -5, -2 iv) Rational numbers 1,1/2, -2, 0.5, 4\(\frac12\) ,-33/7, 0, 4/7,0.\(\bar3\), 22, -5, 2/19, 0.125 etc. Would you leave out any of the given numbers from rational numbers? No Is every natural number, whole number and integer is a rational number? Yes |
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166. |
What should be added to \((\frac{1}{2}+\frac{1}{3}+\frac{1}{5})\) to get 3? |
Answer» Let us consider a number as x to be added to (1/2 + 1/3 + 1/5) to get 3 \(x+(\frac{1}{2}+\frac{1}{3}+\frac{1}{5})=3\\\frac{(30x+1\times15+1\times10+1\times6)}{30}=3\\30x+15+10+6=3\times30\\30x+31=90\\30x=90-31\\x=\frac{59}{30}\) \(\therefore\) the required number is \(\frac{59}{30}\) |
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167. |
A car is moving at an average speed of \(60\frac{2}{5}\) km/hr. How much distance will it cover in \(6\frac{1}{4}\)hours? |
Answer» Speed of car \(=60\frac{2}{5}\,km/hr\) Total hours \(=6\frac{1}{4}\,hrs\) Total Distance = Speed of car × Total hours \(=60\frac{2}{5}\,km/hr\times6\frac{1}{4}\,hrs\) \(=\frac{302}{5}\,km/hr\times\frac{25}{4}\,hrs\) \(=\frac{7550}{20}\,km\) \(=\frac{755}{2}\,km\) \(=377\frac{1}{2}\,km\) Therefore, Total Distance \(=377\frac{1}{2}\,km\) |
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168. |
If \(\frac{3}{5}\) of a number exceeds its \(\frac{2}{7}\) by \(44\) , find the number. |
Answer» Let the number be x \(\frac{3}{5}\) of x \(=\frac{3}{5}\text{x}\) \(\frac{2}{7}\) of x \(=\frac{2}{7}\text{x}\) According to the question, \(\frac{3}{5}\text{x}-\frac{2}{7}\text{x}=44\) \(\Rightarrow\) \(\frac{3\text{x}\times7-2\text{x}\times5}{35}=44\) \(\Rightarrow\) \(\frac{21\text{x}-10\text{x}}{35}=44\) \(\Rightarrow\) \(\frac{11}{35}\times\text{x}=44\) \(\Rightarrow\) \(\text{x}=44\div\frac{11}{35}\) \(\Rightarrow\) \(\text{x}=44\times\frac{35}{11}\) \(\Rightarrow\) \(\text{x}=\frac{1540}{11}\) \(\Rightarrow\) \(\text{x}=140\) The number is 140 |
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169. |
What number should be subtracted from \(\frac{3}{7}\) to get \(\frac{5}{4}\) ? |
Answer» Suppose x be the rational number to be subtracted to \(\frac{3}{7}\) to get \(\frac{5}{4}\) Then, \(\frac{3}{7}\) - x = \(\frac{5}{4}\) -x = \(\frac{5}{4}\) - \(\frac{3}{7}\) -x = \(\frac{5\times 7-3\times 4}{28}\) -x = \(\frac{35-12}{28}\) -x = - \(\frac{23}{28}\) Therefore, The required number x = - \(\frac{23}{28}\) |
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170. |
What should be added to \(\frac{2}{3}+\frac{3}{5}\) to get \(\frac{-2}{15}\) ? |
Answer» Let us consider a number as x to be added to (2/3 + 3/5) to get -2/15 \(\therefore\)the required number is \(\frac{-7}{5}\) |
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171. |
Verify the property x + y = y + x of rational numbers by taking x = -2/3, y = -5/6. |
Answer» In the question is given to verify the property = x + y = y + x Where, x = -2/3, y = -5/6 Then, -2/3 + (-5/6) = -5/6 + (-2/3) LHS = -2/3 + (-5/6) = -2/3 – 5/6 The LCM of the denominators 3 and 6 is 6 (-2/3) = [(-2×2)/ (3×2)] = (-4/6) and (-5/6) = [(-5×1)/ (6×1)] = (-5/6) Then, = – 4/6 – 5/6 = (- 4 – 5)/ 6 = – 9/6 RHS = -5/6 + (-2/3) = -5/6 – 2/3 The LCM of the denominators 6 and 3 is 6 (-5/6) = [(-5×1)/ (6×1)] = (-5/6) and (-2/3) = [(-2×2)/ (3×2)] = (-4/6) Then, = – 5/6 – 4/6 = (- 5 – 4)/ 6 = – 9/6 By comparing LHS and RHS LHS = RHS ∴ -9/6 = -9/6 Hence x + y = y + x |
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172. |
Verify the property x + y = y + x of rational numbers by taking x = -2/5, y = – 9/10. |
Answer» In the question is given to verify the property = x + y = y + x Where, x = -2/5, y = -9/10 Then, -2/5 + (-9/10) = -9/10 + (-2/5) LHS = -2/5 + (-9/10) = -2/5 – 9/10 The LCM of the denominators 5 and 10 is 10 (-2/5) = [(-2×2)/ (5×2)] = (-4/10) and (-9/10) = [(-9×1)/ (10×1)] = (-9/10) Then, = – 4/10 – 9/10 = (- 4 – 9)/ 10 = – 13/10 RHS = -9/10 + (-2/5) = -9/10 – 2/5 The LCM of the denominators 10 and 5 is 10 (-9/10) = [(-9×1)/ (10×1)] = (-9/10) and (-2/5) = [(-2×2)/ (5×2)] = (-4/10) Then, = – 9/10 – 4/10 = (- 9 – 4)/ 10 = – 13/10 By comparing LHS and RHS LHS = RHS ∴ -9/6 = -9/6 Hence x + y = y + x |
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173. |
Find the area of a rectangular park which is \(36\frac{3}{5}\) m long and \(16\frac{2}{5}\) m board. |
Answer» Length of park \(=36\frac{3}{5}\,m\) Breadth of park \(=16\frac{2}{3}\,m\) \(=36\frac{3}{5}\,m\times16\frac{2}{3}\,m\) \(=\frac{183}{5}\,m\times\frac{50}{3}\,m\) \(=\frac{183\times50}{5\times3}\,m\) \(=\frac{9150}{15}\,m^2\) \(=610\,m^2\) Hence, Area of park \(=610\,m^2\) |
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174. |
Verify the property x + y = y + x of rational numbers by taking x = ½, y = ½. |
Answer» In the question is given to verify the property = x + y = y + x Where, x = ½, y = ½ Then, ½ + ½ = ½ + ½ LHS = ½ + ½ = (1 + 1)/2 = 2/2 = 1 RHS = ½ + ½ = (1 + 1)/2 = 2/2 = 1 By comparing LHS and RHS LHS = RHS ∴ 1 = 1 Hence x + y = y + x |
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175. |
Divide the sum of 65/12 and 12/7 by their difference. |
Answer» The sum is = 65/12 + 12/7 The difference is = 65/12 – 12/7 When we divide, = (65/12 + 12/7) / (65/12 – 12/7) = ((65×7 + 12×12)/84) / ((65×7 – 12×12)/84) = ((455+144)/84) / ((455 – 144)/84) = (599/84) / (311/84) = 599/84 × 84/311 = 599/311 |
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176. |
What number should be subtracted from \((\frac{3}{4}-\frac{2}{3})\) to get \(\frac{-1}{6}\) ? |
Answer» Let us consider a number as x to be subtracted from (3/4 – 2/3) to get -1/6 \((\frac{3}{4}-\frac{2}3)-x=\frac{-1}6\\x=\frac{3}{4}-\frac{2}{3}+\frac{1}{6}\\x=\frac{(3\times3-2\times4)}{12}+\frac{1}{6}\\=\frac{(9-8)}{12}+\frac{1}{6}\\=\frac{(1\times1+1\times2)}{12}\\=\frac{3}{12}\\=\frac{1}{4}\) \(\therefore\) the required number is \(\frac{1}{4}\) |
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177. |
What number should be subtracted from \(\frac{3}{7}\) to get \(\frac{5}{4}\)? |
Answer» Let the number be x to subtracted from 3/7 to get 5/4 \(\frac{3}{7}-x=\frac{5}{4}\\x=\frac{3}{7}-\frac{5}{4}\\x=\frac{(3\times4-5\times7)}{28}\\=\frac{(12-35)}{28}\\=\frac{-23}{28}\) \(\therefore\)the required number is \(\frac{-23}{28}\) |
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178. |
Find the area of square plot of land whose each side measure \(8\frac{1}{2}\) meters. |
Answer» Side of plot \(=8\frac{1}{2}\,m\) Area of plot = Side of plot × Side of plot \(=8\frac{1}{2}\,m\times8\frac{1}{2}\,m\) \(=\frac{17}{2}\,m\times\frac{17}{2}\,m\) \(=\frac{17\times17}{2\times2}\,m\) \(=\frac{289}{4}\,m^2\) \(=72\frac{1}{4}\,m^2\) Hence, Area of plot \(=72\frac{1}{4}\,m^2\) |
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179. |
The product of two numbers is \(\frac{-1}{4}.\) If one of them is \(\frac{-3}{10},\) then the other isA. \(\frac{5}{6}\) B. \(\frac{-5}{6}\) C. \(\frac{4}{3}\) D. \(\frac{-8}{5}\) |
Answer» Let the other number be x Then, \(\frac{-3}{10}\times\text{x}=\frac{-1}{4}\) \(\Rightarrow\) \(\text{x}=\frac{-1}{4}\div\frac{-3}{10}\) \(\Rightarrow\) \(\text{x}=\frac{-1}{4}\times\frac{10}{-3}\) \(\Rightarrow\) \(\text{x}=\frac{-1\times10}{4\times-3}\) \(\Rightarrow\) \(\text{x}=\frac{-10}{-12}=\frac{-10\times-1}{-12\times-1}=\frac{10}{12}\) \(\Rightarrow\) \(\text{x}=\frac{10}{12}=\frac{10\div2}{12\div2}=\frac{5}{6}\) |
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180. |
Fill in the blanks: (-12) ÷ (…. ) = (-6/5) |
Answer» (-12) ÷ (…. ) = (-6/5) Let the required number be (a/b). Then, (-12/1) ÷ (a/b) = (-6/5) ⇒ (a/b) = (-12/1) × (5/-6) ⇒ (a/b) = (-12 × 5) / (1 × -6) ⇒ (a/b) = (-2× 5) / (1×-1) ⇒ (a/b) = (-10/-1) ⇒ (a/b) = 10 |
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181. |
The cost of \(2\frac{1}{3}\) meters of cloth is Rs \(75\frac{1}{4}\). Find the cost of cloth per meter. |
Answer» As we know that 7/3 meters of cloth = Rs 301/4 Let a number be = x So, \(x\times\frac{7}{3}=\frac{301}{4}\) x = (301/4) / (7/3) x = (301/4) × (3/7) = (301×3) / (4×7) = (43×3) / (4×1) = 129/4 = 32.25 |
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182. |
Divide the sum of \(\frac{-13}{5}\) and \(\frac{12}{7}\) by the product of \(\frac{-31}{7}\) and \(\frac{-1}{2}\) |
Answer» According to question, \(\frac{-13}{5}+\frac{12}{7}\) = \(\frac{-91+60}{35}\) = \(\frac{-30}{35}\) = \(\frac{-6}{7}\) And, \(\frac{-31}{7}\times \frac{1}{2}\) = \(\frac{-31}{14}\) Now, We have to divide \(\frac{-6}{7}\) by \(\frac{-31}{14}\) Therefore = \(\frac{-6}{7}\times \frac{14}{31}\) = \(\frac{-12}{31}\) |
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183. |
Divide the sum of -(13/5) and 12/7 by the product of -(13/7) and -(1/2). |
Answer» Sum of -13/5 and 12/7 = \(\frac{-13}{5}\,+\,\frac{12}{7} = \frac{-13\,\times\,7\,+\,12\,\times\,5}{35}\) \(\frac{-91\,+\,60}{35}=\frac{-31}{35}\)...............(1) the product of -13/7 and -1/2 = \((\frac{-13}{7})\,\times\,(\frac{-1}{2})= \frac{13}{14}\).................(2) ∴ (1) % (2) = \(\frac{-31}{35}\,\div \,\frac{13}{14}= \frac{-31}{35}\,\times\,\frac{14}{13}= \frac{-62}{65}\) |
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184. |
Verify the property x + y = y + x of rational numbers by taking x = -3/7, y = 20/21. |
Answer» In the question is given to verify the property = x + y = y + x Where, x = -3/7, y = 20/21 Then, -3/7 + 20/21 = 20/21 + (-3/7) LHS = -3/7 + 20/21 The LCM of the denominators 7 and 21 is 21 (-3/7) = [(-3×3)/ (7×3)] = (-9/21) and (20/21) = [(20×1)/ (21×1)] = (20/21) Then, = – 9/21 + 20/21 = (- 9 + 20)/ 21 = 11/21 RHS = 20/21 + (-3/7) The LCM of the denominators 21 and 7 is 21 (20/21) = [(20×1)/ (21×1)] = (20/21) and (-3/7) = [(-3×3)/ (7×3)] = (-9/21) Then, = 20/21 – 9/21 = (20 – 9)/ 21 = 11/21 By comparing LHS and RHS LHS = RHS ∴ 11/21 = 11/21 Hence x + y = y + x |
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185. |
What number should be added to \(\frac{-5}{7}\) to get \(\frac{-2}{3}\) ? |
Answer» Suppose x be the rational number to be added to \(\frac{-5}{7}\) to get \(\frac{-2}{3}\) Then, \(\frac{-5}{7}\)+ x = \(\frac{-2}{3}\) x - \(\frac{5}{7}-\frac{2}{3}\) x = \(\frac{5\times 3-2\times 7}{21}\) x = \(\frac{15-14}{21}\) x = \(\frac{1}{21}\) Therefore, The required number x = \(\frac{1}{21}\) |
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186. |
The cost of 7\(\frac23\) meters of cloth is ₹12\(\frac34\) . Find the cost per metre. |
Answer» The cost of 7\(\frac23\) mts ( \(\frac{23}3\) mts ) of cloth = ₹12\(\frac34\) = ₹\(\frac{51}4\) ∴ The cost of 1m cloth = \(\frac{51}{4}\,\div\,\frac{23}3=\frac{51}4\,\times\,\frac3{23}\) = \(\frac{153}{92}\) = ₹ 1.66 |
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187. |
One liters of petrol costs Rs. \(63\frac{3}{4}\) What is the cost of 34 liters of petrol? |
Answer» Cost of one litre petrol \(=Rs\,63\frac{3}{4}=Rs\,\frac{255}{4}\) Cost of 34 litre petrol = 34 × Cost of one litre petrol \(=34\times\,Rs\,\frac{255}{4}\) \(=Rs\,\frac{34\times255}{4}\) \(=Rs\,\frac{8670}{4}\) \(=Rs\,\frac{4335}{2}\) \(=Rs\,2167\frac{1}{2}\) Cost of 34 litre petrol \(=Rs\,2167\frac{1}{2}\) |
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188. |
Divide the sum of (65/12) and (8/3) by their difference. |
Answer» ((65/12) + (8/3)) ÷ ((65/12) – (8/3)) = ((65/12) + (32/12)) ÷ ((65/12) – (32/12)) = (65 + 32)/12 ÷ (65 -32)/12 = (65 + 32)/12 × (12/ (65 – 32) = (65 + 32)/ (65 – 32) = (97/33) |
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189. |
Divide the sum of (65/12) and (8/3) by their difference. |
Answer» First we have to find the sum of (65/12) + (8/3) LCM of 12 and 3 is 12 Then, = (65 × 1) / (12×1) = (65/12) = (8× 4) / (3× 4) = (32/12) Now, = (65 + 32)/12 = (97/12) Now find the difference of (65/12) – (8/3) LCM of 12 and 3 is 12 Then, = (65 × 1) / (12×1) = (65/12) = (8× 4) / (3× 4) = (32/12) Now, = (65 – 32)/12 = (33/12) Now divide (97/12) ÷ (33/12) = (97/12) × (12/33) = (97 × 12) / (12× 33) = (97 × 1) / (1× 33) = (97/33) |
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190. |
\((\frac{-5}{6}\div\frac{-2}{3})= \,?\)A. \(\frac{-5}{4}\) B. \(\frac{5}{4}\) C. \(\frac{-4}{5}\) D. \(\frac{4}{5}\) |
Answer» \(\frac{-5}{6}\div\frac{-2}{3}\) \(=\frac{-5}{6}\times\frac{3}{-2}\) \(=\frac{-5\times3}{6\times-2}\) \(=\frac{-15}{-12}=\frac{-15\times-1}{-12\times-1}=\frac{15}{12}\) \(=\frac{15}{12}=\frac{15\div3}{12\div3}=\frac{5}{4}\) |
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191. |
Evaluate: (-5/-8) – (-3/4) |
Answer» (-5/-8) – (-3/4) First we write each of the given numbers with a positive denominator. (-5/-8) = [(-5× (-1))/ (-8×-1)] = (5/8) We have: = (5/8) – (-3/4) = (5/8) + (additive inverse of -3/4) = (5/8) + (3/4) LCM of 8 and 4 is 8 Express each of the given rational numbers with the above LCM as the common denominator. Now, = [(5×1)/ (8×1)] = (5/8) = [(3×2)/ (4×2)] = (6/8) Then, = (5/8) + (6/8) = (5+6)/8 = (11/8) |
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192. |
The sum of two rational numbers is (4/21). If one of them is (5/7), find the other. |
Answer» Let the required number be x. Then, = (5/7) + x = (4/21) By sending (5/7) from left hand side to the right hand side it changes to – (5/7) x = (4/21) – (5/7) LCM of 21 and 7 is 21 Express each of the given rational numbers with the above LCM as the common denominator. Now, = [(4×1)/ (21×1)] = (4/21) = [(5×3)/ (7×3)] = (15/21) Then, = (4/21) – (15/21) = (4-15)/21 = (-11/21) Hence the required number is (-11/21) |
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193. |
\(\frac{4}{3}\div\,?=\frac{-5}{2}\) A. \(\frac{-8}{5}\) B. \(\frac{8}{5}\) C. \(\frac{-8}{15}\) D. \(\frac{8}{15}\) |
Answer» \(\frac{4}{3}\div\text{x}=\frac{-5}{2}\) \(\Rightarrow\) \(\text{x}=\frac{4}{3}\div\frac{-5}{2}\) \(\Rightarrow\) \(\text{x}=\frac{4}{3}\times\frac{2}{-5}\) \(\Rightarrow\) \(\text{x}=\frac{4\times2}{3\times-5}\) \(\Rightarrow\) \(\text{x}=\frac{8}{-15}=\frac{8\times-1}{-15\times-1}=\frac{-8}{15}\) |
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194. |
A rational number between \(\frac{-2}{3}\) and \(\frac{1}{2}\) isA. \(\frac{-1}{6}\) B. \(\frac{-1}{12}\) C. \(\frac{-5}{6}\) D. \(\frac{5}{6}\) |
Answer» Rational number between \(\frac{-1}{3}\) and \(\frac{1}{2}\) \(=\frac{1}{2}(\frac{-2}{3}+\frac{1}{2})\) \(=\frac{1}{2}(\frac{-2\times2+1\times3}{6})\) \(=\frac{1}{2}(\frac{-4+3}{6})\) \(=\frac{1}{2}\times\frac{-1}{6}\) \(=\frac{-1}{12}\) |
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195. |
The sum of the two numbers is (5/9). If one of the numbers is (1/3), find the other. |
Answer» Given sum of two numbers is (5/9) And one them is (1/3) Let the unknown number be x x + (1/3) = (5/9) x = (5/9) – (1/3) LCM of 3 and 9 is 9 Consider (1/3) = (1/3) × (3/3) = (3/9) On substituting we get x = (5/9) – (3/9) x = (5 – 3)/9 x = (2/9) |
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196. |
Divide the sum of \(\frac{65}{12}\) and \(\frac{8}{3}\) by their differ-renice. |
Answer» According to the question, \((\frac{65}{12}+\frac{8}{3})\div(\frac{65}{12}-\frac{8}{3})\) = \((\frac{65\times1+8\times4}{12})\div(\frac{65\times1-8\times4}{12})\) = \((\frac{65+32}{12})\div(\frac{65-32}{12})\) = \((\frac{97}{12})\div(\frac{33}{12})\) = \(\frac{97}{12}\times\frac{12}{33}\) = \(\frac{97}{33}\) |
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197. |
An aeroplane covers 1020 km in an hour. How much distance will it cover in \(4\frac{1}{6}\) hours? |
Answer» Distance covered in one hour = 1020 km Distance covered in \(4\frac{1}{6}\) hours \(=4\frac{1}{6}\times\) Distance covered in one hour \(=4\frac{1}{6}\times1020\,km\) \(=\frac{25}{6}\times1020\,km\) \(=\frac{25\times1020}{6}\,km\) \(=\frac{25500}{6}\,km\) \(=4250\,km\) Distance covered in \(4\frac{1}{6}\) hours \(=4250\,km\) |
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198. |
Multiply \(\frac2{11}\) by the reciprocal of \(\frac{-5}{14}\) |
Answer» The reciprocal of \(\frac{-5}{14} \,is\,\frac{-14}{5}\) ( \(\because\) \((\frac{-5}{14})\,\times\,(\frac{-14}{5})=1)\) ∴ The product of \(\frac{2}{14} \,and\,\frac{-14}{5} \,is\,\frac{2}{11}\,\times\,(\frac{-14}{5}) = \frac{-28}{55}\) |
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199. |
Reciprocal of \(\frac{-7}{9}\) isA. \(\frac{9}{7}\)B. \(\frac{-9}{7}\) C. \(\frac{7}{9}\) D. none of these |
Answer» Reciprocal of \(\frac{-7}{9}=\frac{9}{-7}\) \(\frac{9}{-7}=\frac{9\times-1}{-7\times-1}=\frac{-9}{7}\) |
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200. |
Evaluate each of the following:(i) (2/3) – (3/5)(ii) (-4/7) – (2/-3)(iii) (4/7) – (-5/-7)(iv) -2 – (5/9) |
Answer» (i) Given (2/3) – (3/5) The LCM of 3 and 5 is 15 Consider (2/3) = (2/3) × (5/5) = (10/15) Now again (3/5) = (3/5) × (3/3) = (9/15) (2/3) – (3/5) = (10/15) – (9/15) = (1/15) (ii) Given (-4/7) – (2/-3) The LCM of 7 and 3 is 21 Consider (-4/7) = (-4/7) × (3/3) = (-12/21) Again (2/-3) = (-2/3) × (7/7) = (-14/21) (-4/7) – (2/-3) = (-12/21) – (-14/21) = (-12 + 14)/21 = (2/21) (iii) Given (4/7) – (-5/-7) (4/7) – (5/7) = (4 -5)/7 = (-1/7) (iv) Given -2 – (5/9) Consider (-2/1) = (-2/1) × (9/9) = (-18/9) -2 – (5/9) = (-18/9) – (5/9) = (-18 -5)/9 = (-23/9) |
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