Question

Arun's present age in years is 40% of Barun's. In another few years, Arun's age will be half of Barun's. By what percentage will Barun's age increase during this period?

• A. 26
• B. 18
• C. 20
• D. 23

Answer 1

Answer: (C)

20

Answer 2

Let Barun’s age be $10x.$
Arun’s age is $4x.$
The difference of these ages is $6x,$ a constant.
When Arun’s age is 50% of Barun’s age, this difference would also be 50%, i.e., Barun’s age at that stage would be $12x.$ It would increase by 20%