The present age of two persons A and B are 36 and 50 years respectively.  If after x years the ratio of their age will be 3 : 4, then the value of x is?

6

Ratio of present age of A and B = 36 : 50 = 18 : 25 *(Where 1R = 2)*

After x years ratio will be = (18R + x) : (25R + x)

ATQ,

⇒ \(\frac{18R\;+\;x}{25R\;+\;x}\) = \(\frac{3}{4}\)

⇒ 72R + 4x = 75R + 3x

⇒ 3R = x

⇒ x = 3 × 2 = 6             (1R = 2)

OR

 A         B

36   :    50

+6       +6  (according to option)

 42       56

  3    :    4    ←  proof

Hence, option (2) → 6