Rael is 5 years old now. His sister is 15 years older than him. How old will Rael be when his age is
25 of his sister's age?
| |
Rael |
His sister |
Difference |
| Before |
|
|
15 |
| Change |
+ ? |
+ ? |
|
| After |
2 u |
5 u |
3 u |
The difference in the age between Rael and his sister at first and in the end remains unchanged.
Number of years that his sister is older than Rael
= 5 u - 2 u
= 3 u
3 u = 15
1 u = 15 ÷ 3 = 5
Rael's age when his age is
25 of his sister's age
= 2 u
= 2 x 5
= 10
Answer(s): 10
