The present age of Sanyal is 3 times the present age of his son. Six years hence, the ratio of their ages will be 5 : 2 respectively. The present age of Sanyal is:

Let us assume the present age of son be x then his father present age will be 3x.
According to question,
Six years hence, the ratio of their ages will be 5 : 2 respectively
(3x + 6)/(x+6) = 5/2
? (3x + 6)2 = 5(x+6)
? 6x + 12 = 5x + 30
? x = 18
Hence, age of Sanyal = 3 x 18 = 54 years