

InterviewSolution
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Express each of the following decimals in the form \(\frac{p}q\);(i) 0.\(\overline4\)(ii) \(0.\overline{37}\)(iii) \(0.\overline{54}\)(iv) \(0.\overline{621}\)(v) \(125.\overline3\)(vi) \(4.\overline7\)(vii) \(0.4\overline7\) |
Answer» (i) Let x =\(0.\overline4\) Now, x = \(0.\overline4\) = 0.444… (1) Multiplying both sides of equation (1) by 10, we get, 10x = 4.444… (2) Subtracting equation (1) by (2) 10x – x = 4.444… - 0.444… \(9\times = 4\) x = \(\frac{4}{9}\) Hence, \(0.\overline4 = \frac{4}{9}\) (ii) Let x = \(0.\overline{37}\) Now, x = 0.3737…. (1) Multiplying equation (1) by 10 10x = 3.737…. (2) Multiplying equation (2) by 10 100x = 37.3737…. (3) 100x – x = 37 99x = 37 \(x = \frac{37}{99}\) Hence, \(0.\overline{37}\) \(= \frac{37}{99}\) (iii) Now x \(= 0.\overline{54}\) = 0.5454… (i) Multiplying both sides of equation (i) by 100, we get 100x = 54.5454…. (ii) Subtracting (i) by (ii), we get 100x – x = 54.5454…. – 0.5454…. 99x = 54 \(x = \frac{54}{99}\) (iv) Now x \(= 0\overline{621}\) = 0.621621…. (i) Multiplying both sides by 1000, we get 1000x = 621.621621…. (ii) Subtracting (i) by (ii), we get 1000x – x = 621.621621…. – 0.621621…. 999x = 621 \(x = \frac{621}{999}\) \(= \frac{23}{37}\) (v) Now x = \(125.\overline3\) = 125.3333…. (i) Multiplying both sides of equation (i) by 10, we get 10x = 1253.3333…. (ii) Subtracting (i) by (ii), we get 10x – x = 1253.3333…. – 125.3333…. 9x = 1128 x = 1128 / 9 = 376/3 (vi) Now x \(= 4.\overline7\) = 4.7777…. (i) Multiplying both sides of equation (i) by 10, we get 10x = 47.7777…. (ii) 10x – x = 47.7777…. – 4.7777…. \(9\times = 43\) \(x = \frac{43}{9}\) (vii) Now, x = \(0.4\overline7\) = 0.47777…. Multiplying both sides by 10, we get 10x = 4.7777…. (i) Multiplying both sides of equation (i) by 10, we get 100x = 47.7777…. (ii) Subtracting (i) from (ii), we get 100x – 10x = 47.7777…. – 4.7777…. \(90\times = 43\) x \(= \frac{43}{90}\) |
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