Marion is 3 years old. Her father is 31 years old. How old will Marion be when her father is three times her age?
| |
Marion |
Her father |
Difference |
| Before |
3 |
31 |
28 |
| Change |
+ ? |
+ ? |
|
| After |
1 u |
3 u |
2 u |
The difference in the age between Marion and her father remains unchanged.
Difference in their age at first
= 31 - 3
= 28
Difference in their age in the end
= 3 u - 1 u
= 2 u
2 u = 28
1 u = 28 ÷ 2 = 14
Marion's age when her father is three times her age
= 1 u
= 14
Answer(s): 14
