A person's present age is two-fifth of the age of his mother. After 8 years, he will be one-half of the age of his mother. How old is the mother at present

Answer: Option C

Explanation:

Let B's age = x years.
Then, As age = (x+ 9) years.
(x+9+10)=2(x—10)
hence x=39.
Present age of B = 39 years

Answer: Option B

Explanation:

Let the mother's present age be x years.
Then, the person's present age = (2/5 x) years.

=> (2/5 x + 8/2) = 1 (x + 8)
=> 2(2x + 40) = 5(x + 8)
=> x = 40

Answer: Option D

Explanation:

Let the present ages are 4x, 7x, 9x.
=> (4x-8) + (7x-8) + (9x-8) = 56
=> 20x = 80
=> x = 4

So their present ages are: 16,28,36

Answer: Option B

Explanation:

Let their ages 10 years ago is x, 2x and 3x years.
10 + 2x + 10 + 3x + 10 = 90 hence x= 10
B’s present age = (2x + 10) =30 years

Answer: Option B

Explanation:

Present age is 4x and 3x,
=> 4x + 6 = 26 => x = 5

So Deepak age is = 3(5) = 15