5 years ago, the average age of Ram and Shyam was 20 years. Now, the average age of Ram, Shyam and Mohan is 30 years. What will be Mohan's age 10 years hence?

Let us assume the present age of Ram R, Shyam S and Mohan M.
5 years ago, Ram age = R - 5
5 years ago, Shyam age = S - 5
5 years ago, Mohan age = M - 5
According to question,
5 years ago, the average age of Ram and Shyam was 20 years,
(5 years ago, Ram age + 5 years ago, Shyam age) /2 = 20
(R - 5 + S - 5 )/2 = 20
R + S = 40 + 10 = 50 ................(1)
Now Again according to question,
Now , the average age of Ram, Shyam and Mohan is 30 years
(R + S + M)/3 = 30
R + S + M = 90
Pu the value of R + S from equation (1)
50 + M = 90
M = 90 - 50 = 40
The present age of Mohan = 40 years
10 years hence, the age of Mohan = 40 + 10 = 50 years