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Arrange the following rational numbers in descending order:(i) \(-2,\frac{-13}{6},\frac{8}{-3},\frac{1}{3}\) (ii) \(\frac{-3}{10},\frac{7}{-15},\frac{-11}{20},\frac{17}{-30}\) (iii) \(\frac{-5}{6},\frac{-7}{10},\frac{-13}{18},\frac{23}{-24}\) (iv) \(\frac{-10}{11},\frac{-19}{11},\frac{-23}{33},\frac{-39}{44}\) |
Answer» (i) \(-2 = \frac{-2}{1}\) And, \(\frac{8}{-3} = \frac{8\times-1}{-3\times-1} = \frac{-8}{3}\) Since, the denominators of all the numbers are different therefore we will take LCM of the denominators. LCM of 1, 6and 3 = 6 \(\frac{-2}{1}= \frac{-2\times6}{1\times6} = \frac{-12}{6}\) \(\frac{-13}{6}= \frac{-13\times1}{6\times1} = \frac{-13}{6}\) \(\frac{-8}{3}= \frac{-8\times2}{3\times2} = \frac{-16}{6}\) \(\frac{1}{3}= \frac{1\times2}{3\times2} = \frac{-2}{6}\) Clearly, 2 > -12 > -13 > -16 Therefore, \(\frac{2}{6}>\frac{-12}{6}>\frac{-13}{6}>\frac{-16}{6}\) Hence, \(\frac{1}{3}>\frac{-2}{1}>\frac{-13}{6}>\frac{-8}{3}\) (ii) \(\frac{7}{-15}= \frac{7\times-1}{-30\times-1} = \frac{-17}{30}\) And, \(\frac{17}{-30}= \frac{17\times-1}{-30\times-1} = \frac{-17}{30}\) Since, the denominators of all the numbers are different therefore we will take LCM of the denominators. LCM of 10, 15, 20 and 30 = 60 \(\frac{-3}{10}= \frac{-3\times6}{10\times6} = \frac{-18}{60}\) \(\frac{-7}{15}= \frac{-7\times4}{15\times4} = \frac{-28}{60}\) \(\frac{-11}{20}= \frac{-11\times3}{20\times3} = \frac{-33}{60}\) \(\frac{-17}{30}= \frac{-17\times2}{30\times2} = \frac{-34}{60}\) Clearly, -18>-28>-33>-34 Therefore, \(\frac{-18}{60}>\frac{-28}{60}>\frac{-33}{60}>\frac{-34}{60}\) Hence, \(\frac{-3}{10}>\frac{-7}{15}>\frac{-11}{20}>\frac{-17}{30}\) (iii) \(\frac{23}{-24} = \frac{23\times-1}{-24\times-1} = \frac{-23}{24}\) Since, the denominators of all the numbers are different therefore we will take LCM of the denominators. LCM of 6, 12, 18 and 24 = 72 \(\frac{-5}{6}= \frac{-5\times12}{6\times12} = \frac{-60}{72}\) \(\frac{-7}{12}= \frac{-7\times6}{12\times6} = \frac{-42}{72}\) \(\frac{-13}{18}= \frac{-13\times4}{18\times4} = \frac{-52}{72}\) \(\frac{-23}{24}= \frac{-23\times3}{24\times3} = \frac{-69}{72}\) Clearly, -42>-52>-60>-69 Therefore, \(\frac{-42}{72}>\frac{-52}{72}>\frac{-60}{72}>\frac{-69}{72}\) Hence, \(\frac{-7}{12}>\frac{-13}{18}>\frac{-5}{6}>\frac{-23}{24}\) (iv) Since, the denominators of all the numbers are different therefore we will take LCM of the denominators. LCM of 11, 22, 33 and 44 = 132 \(\frac{-10}{11}= \frac{-10\times12}{11\times12} = \frac{-120}{132}\) \(\frac{-19}{22}= \frac{-19\times6}{22\times6} = \frac{-144}{132}\) \(\frac{-23}{33}= \frac{-23\times4}{33\times4} = \frac{-92}{132}\) \(\frac{-39}{44}= \frac{-39\times3}{44\times3} = \frac{-117}{132}\) Clearly, -92>-114>-117>-120 Therefore, \(\frac{-92}{132}>\frac{-114}{132}>\frac{-117}{132}>\frac{-120}{132}\) Hence, \(\frac{-23}{33}>\frac{-19}{22}>\frac{-39}{44}>\frac{-10}{11}\) |
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