Mark is 6 years old now. His sister is 25 years older than him. How old will Mark be when his age is
38 of his sister's age?
| |
Mark |
His sister |
Difference |
| Before |
|
|
25 |
| Change |
+ ? |
+ ? |
|
| After |
3 u |
8 u |
5 u |
The difference in the age between Mark and his sister at first and in the end remains unchanged.
Number of years that his sister is older than Mark
= 8 u - 3 u
= 5 u
5 u = 25
1 u = 25 ÷ 5 = 5
Mark's age when his age is
38 of his sister's age
= 3 u
= 3 x 5
= 15
Answer(s): 15
