Correct Answer - Option 2 : 3 : 5
Given:
6 year ago the ratio of son and his father = 6 : 11
6 year hence their ratio will be = 9 : 14
Concept used:
The difference between their ages will always same.
In a : b and c : d if b - a = d - c then b - d = a - c
Calculation:
6 year ago, Son : Father = 6 : 11
Age difference = 11 - 6 = 5
6 year hence, Son : Father = 9 : 14
Age difference = 14 - 9
⇒ 5
As the age difference is already the same, we can say changes of 3R in son's age as well as father's age is due to the gap of 12 years.
So, 3R = 12 year
⇒ R = 4 year
6 year = (3/2)R
To find their present ratio add the (3/2)R to the ratio of 6 year ago.
Son : Father = 6 + (3/2) : 11 + (3/2)
⇒ (15/2) : (25/2)
⇒ 3 : 5
∴ The ratio of their present age is 3 : 5.
