Question

When benny's sister is 24, Benny's age will be 125% of her age. How old will Benny be then, and is Benny is 12 years old now, how old is penny now?

Answer 1

A. 30

B. 6

Explanation:

We'll use P for Penny's age and B for Benny's age. When Penny is 24, Benny will be 1.25 her age. Thus:

B = 1.25 * 24

(benny is 25% older than her)

So Benny's age then will be 1.25 * 24 = 30.

When Benny is 30, Penny will be 24. This means that he is older than her by 6 years. Think about it for a second: Benny will always be 6 years older than her. You can write that as:

B = P + 6

If Benny is 12 years old now,

12 = P + 6

Subtract 6 from both sides and you get

6 = P

or P = 6

Penny is 6 years old when Benny is 12.