The ratio between the present ages of A and B is 4 : 5. If the ratio between their ages 4 yr hence becomes 14 : 17, then what is B's age at present?

A) 30 yr

B) 28 yr

C) 34 yr

D) Data inadequate

Correct answer:
A) 30 yr

Description for Correct answer:
Let the ages of A and B are 4x and 5x yr, respectively.
According to the question

\( \large\frac{4x + 4}{5x + 4} = \frac{14}{17} \)

68x + 68 = 70x + 56

2x = 12 = > x = 6

Hence, present age of B = 5 x 6 = 30 yr


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