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The ratio of ages of R and S, 3 years ago was 5 : 7 and the ratio of age of T and U, 3 years from now will be 11 : 5. At present, T is 6 years older than S. The average age of R and U is 15 years.From the statement given in the above question, which of the following can be determined?(A) Present age of R (B) Present age of S (C) Present age of T (D) Present age of U1. Only S and T2. Only R and U3. Only R, S and U4. All R, S, T, U5. None of them |
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Answer» Correct Answer - Option 4 : All R, S, T, U Let the present age of R, S, T and U be ‘r’, ‘s’, ‘t’ and ‘u’ years respectively. So, (r - 3)/(s – 3) = 5/7 ⇒ 5s – 15 = 7r – 21 ⇒ 7r – 5s = 6 ----(i) Also, (t + 3) / (u + 3) = 11/5 ⇒ 11u + 33 = 5t + 15 ⇒ 5t – 11u = 18 ----(ii) Now, t = s + 6 Putting in (ii) 5(s + 6) – 11 u = 18 ⇒ 11u – 5s = 12 ⇒ 11u + 6 – 7r = 12 ⇒ 11u – 7r = 6 ----(iii) Also, (r + u)/2 = 15 ⇒ r + u = 30 ----(iv) (iii) + 7 × (iv) given, 18u = 216 ⇒ u = 12 ∴ r = 30 – 12 = 18 From (i), 7 × 18 – 5s = 6 ⇒ 5s = 120 ⇒ s = 24 ∴ t = s + 6 = 24 + 6 = 30 The present ages of all of them can be determined. |
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