7 years ago, the ages (in years) of A and B were in the ratio 4 : 5 and 7 years hence, that will be in the ratio 6 : 7. The present age of B is:
Answer & explanation
Correct answer: option 1
Ratio of age of A and B (7 years ago) = 4 : 5
Ratio of age of A and B (7 years hence) = 6 : 7
ATQ,
⇒ \(\frac{4R + 14}{5R + 14}\) = \(\frac{6}{7}\)
⇒ 28R + 98 = 30R + 84
⇒ 2R = 14
⇒ 1R = 7
So,
Ages of A and B (7 years ago) = 4 x 7, 5 x 7 = 28, 35
Present ages = (28 + 7), (35 + 7) = 35, 42