Sarah is 4 years old. Her uncle is 34 years old. How old will Sarah be when her uncle is three times her age?
| |
Sarah |
Her uncle |
Difference |
| Before |
4 |
34 |
30 |
| Change |
+ ? |
+ ? |
|
| After |
1 u |
3 u |
2 u |
The difference in the age between Sarah and her uncle remains unchanged.
Difference in their age at first
= 34 - 4
= 30
Difference in their age in the end
= 3 u - 1 u
= 2 u
2 u = 30
1 u = 30 ÷ 2 = 15
Sarah's age when her uncle is three times her age
= 1 u
= 15
Answer(s): 15
