The ratio between the present ages of P and Q is 6 : 7. If Q is 4 years old than P, what will be the ratio of the ages of P and Q after 4 years? Choose the correct choice from the following: A) 3 : 4 B) 3 : 5 C) 4 : 3 D) 7 : 8 E) None
Sol.   Let P's age and Q's age be 6x years and 7x years respectively.   Then, 7x - 6x = 4 ⇔ x = 4.   ∴ Required ratio = (6x + 4) : (7x + 4) = 28 : 32 = 7 : 8.   Answer 7 : 8
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The ratio between the present ages of P and Q is 6 : 7. If Q is 4 years old than P, what will be the ratio of the ages of P and Q after 4 years?