The sum of the ages of a father and son is 45 years. Five years ago, the product of their ages was four times the fathers age at that time. The present age of father and son

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 six years ago the age of Kunal and Sagar are 6x and 5x resp.
then,
\begin{aligned}
=> \frac{(6x+6)+4}{(5x+6)+4} = \frac{11}{10}
\end{aligned}
\begin{aligned}
<=> 10(6x+10) = 11(5x+10)
\end{aligned}
\begin{aligned}
<=> 5x = 10 => x = 2
\end{aligned}

So Sagar age is (5x+6) = 16

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 the age of younger person is x,
Then elder person age is (x+16)
=> 3(x-6) = (x+16-6) [6 years before]
=> 3x-18 = x+10
=> x = 14.
So other person age is x + 16 = 30