The present ages of two persons are 36 and 50 years respectively
After n years the age of both persons will be 36 + n and 50 + n respectively.
According to question,
After n years the ratio of their ages will be 3:4,
(36 + n)/(50 + n) = 3/4
⇒ (36 +n) x 4 = 3 x (50 + n)
⇒ 36 x 4 + 4 x n = 50 x 3 + 3 x n
⇒ 144 + 4n = 150 + 3n
⇒ 4n - 3n =150 -144
⇒ n = 6
