The ages of a man and his son is in the ratio of 7: 2. After 15 years, they would be in the ratio of 2 : 1, what was father's age when son was born ?
25 years
58 years
20 years
22 years
Explanation:
Let father age is 7x
And son age is 2x
then after 15 year father age is 7x+15
After 15 year son age is 2x+15
⇒ $\dfrac{7x+15}{2x+15}=\dfrac{2}{1} $ ⇒4x+30=7x+15
⇒4x−7x=15−30
⇒−3x=−15⇒x=5
Hence father present age=7×5=35
Son present age=2×5=10
difference of father and son age=35−10=25
So father age was 25 years when son was born
Let father age is 7x
And son age is 2x
then after 15 year father age is 7x+15
After 15 year son age is 2x+15
⇒ $\dfrac{7x+15}{2x+15}=\dfrac{2}{1} $ ⇒4x+30=7x+15
⇒4x−7x=15−30
⇒−3x=−15⇒x=5
Hence father present age=7×5=35
Son present age=2×5=10
difference of father and son age=35−10=25
So father age was 25 years when son was born