A man was 32 years of age when he had his first son. His wife was 35 years of age when his son attained the age of 7 years. The difference between the age of the father and the mother is ______.

Suppose present age of Mrs. Lata = P years
Present age of son = Q years
? Their total age = 64 years
P + Q = 64 ....... (i)
According to question,
8 years ago , present age of Mrs. Lata - 8 years = 3 × ( present age of her son - 8 years )
? P ? 8 = 3 (Q ? 8)
? P ? 8 = 3Q ? 24
? P ? 3Q = ? 16 ......(ii)
From equations (i) and (ii), we get
4Q = 80 ? Q = 20
Putting the value of Q in eq.(i)
? Age of Mrs. Lata = 64 ? 20 = 44 years

Age of Mahesh = 60 years
Age of Ram = Age of Mahesh - 5 years = 60 ? 5 = 55 years
Age of Raju = Age of Ram - 4 years = 55 ? 4 = 51 years
Age of Babu = Age of Raju - 6 years = 51 ? 6 = 45 years
Age difference between Mahesh and Babu = 60 ? 45 = 15 years

Suppose, the age of Nikhil is 1 year.
Nikhil is 8 years younger than his brother Rohan.
Therefore, age of Rohan = 1 + 8 = 9 years
After 7 years ,
Nikhil will be 8 years old and Rohan will be 16 years old.

Let the present ages of Samir and Saurabh are 8a and 15a years respectively ; .
After 9 years the ages of Samir and Saurabh will be 8a + 9 and 15a + 9.
According to question,
After 9 years the ratio of their ages will be 11 : 18, then
(8a + 9)/ = 11/18
? (8x + 9) x 18 = 11 x (15a + 9)
? 144a + 162 = 165a + 99
? 21a = 63
? a = 3
Hence, difference of their ages = 15a - 8a = 7a = 7 x 3 = 21 years