Let the present ages of Samir and Saurabh are 8a and 15a years respectively.

Correct Option: B

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

Let us assume the present ages of Suresh and his daughter be 2x and x years respectively.

Correct Option: B

Let the present ages of Suresh and his daughter be 2x and x years respectively; then
According to question,
Six years hence, the ratio of their ages would be 23 : 13
(2x + 6) / (x + 6) = 23/13
⇒ (2x + 6) 13 = 23 (x + 6)
⇒ 26x + 78 = 23x + 138
⇒ 3x = 60
∴ x = 20
Hence, present age of Suresh = 2 x 10 = 40 years

Let us assume the present ages of son be Y then his father present age will be Y + 34 years.

Correct Option: B

Let us assume the present ages of son be Y then his father present age will be Y + 34 years. then
12 years ago, father's age = Y + 34 -12
12 years ago, Son's age = Y - 12
Now according to question,
12 years ago, father's age was 18 times the age of his son. then
18( Y - 12 ) = Y + 34 - 12
⇒ 18Y - 216 = Y + 22
⇒ 17Y = 238
∴ Y = 14
Hence, present age of his son = 14 years.

Let the present ages of two person be 4x and 7x years respectively;

Correct Option: B

Let the present ages of two person be 4x and 7x years respectively; then according to question,
7x = 30 + 4x
⇒ 3x = 30
∴ x = 10
Hence, sum of their ages = 4x + 7x = 11x = 11 x 10 = 110 years

Let us assume the age of second son be Y, then age of first son will be Y + 10 and age of father will be (Y + 10 + 30) years respectively;

Correct Option: C

Let us assume the age of second son be Y, then age of first son will be Y + 10 and age of father will be (Y + 10 + 30) years respectively;
then according to question,
sum of their ages be 95 years.
x + x + 10 + x + 10 + 30 = 95
⇒ 3x = 95 - 50
⇒ 3x = 45
∴ x = 15
age of the father = x + 10 + 30
Hence, age of the father = 15 + 10 + 30 = 55 years.