Correct Answer - Option 3 : 5 ∶ 6
Given:
The present age of Rohan and Sohan = 3 ∶ 4
5 years ago the ratio of their age = 2 ∶ 3
Calculation:
Let the age of Rohan and Sohan be 3x and 4x respectively.
5 years back their ages will be (3x – 5) and (4x – 5) respectively.
According to the question,
⇒ (3x – 5) ∶ (4x – 5) = 2 ∶ 3
⇒ (3x – 5)/(4x – 5) = 2/3
⇒ 9x – 15 = 8x – 10
⇒ x = 15 – 10
⇒ x = 5
Present age of Rohan = 3 × 5 = 15
Present age of Sohan = 4 × 5 = 20
10 years from now
Age of Rohan = 15 + 10 = 25
Age of Sohan = 20 + 10 = 30
Ratio of their ages = 25 ∶ 30 = 5 ∶ 6
∴ The required ratio is 5 ∶ 6