The sum of the ages of Ram, Shyam and Mohan is 93 years. Ten years ago, the ratio of their ages was 2 : 3 : 4. The present age of Mohan is:

Let us assume 10 years ago, ages of Ram, Shyam and Mohan were 2x, 3x and 4x years respectively.
Present ages of Ram, Shyam and Mohan will be 2x + 10 , 3x + 10 and 4x + 10 years.
According to question,
2x + 10 + 3x + 10 + 4x + 10 = 93
⇒ 9x + 30 = 93
⇒ 9x = 93 - 30
⇒ 9x = 63
⇒ x = 7
The present age of mohan = 4x + 10 = 4x7 + 10 = 38 years