The total age of A and B is 12 years more than the total age of B and C. C is how many year younger than A

Answer: Option A

Explanation:

Let the present age of P and Q be 3x and 4x respectively.
Ten years ago, P was half of Q in age
=> 2(3x – 10) = (4x – 10)

=> 6x – 20 = 4x – 10

=> 2x = 10

=> x = 5

Answer: Option C

Explanation:

Let sons age = x years. Then fathers age = (45 - x)years.
(x—5)(45—x—5) = 4(45- x - 5) hence (x—5) = 4 so x = 9
Their ages are 36 years and 9 years.

Answer: Option B

Explanation:

Let's Son age is x, then Father age is x+24.
=> 2(x+2) = (x+24+2)
=> 2x+4 = x+26
=> x = 22 years

Answer: Option A

Explanation:

Let P age and Q age is 6x years and 7x years.
Then 7x - 6x = 4 <=> x = 4

So required ratio will be (6x+4): (7x+4) => 28:32 => 7:8

Answer: Option C

Explanation:

From 2nd we get, Present ages of Abhinav and his son is 11x and 6x,

From 1st we get, Abhinav's present age = 2 * Son's age

From 3rd we get, 5 years hence, Abhinav age / Son's age = 12 / 7

From clearly we can get Abhinav age from any of two equations.