David is 4 years old. His uncle is 30 years older than him. In how many years will David's uncle be 4 times as old as David?
| |
His uncle |
David |
Difference |
| Before |
34 |
4 |
30 |
| Change |
+ ? |
+ ? |
|
| After |
4 u |
1 u |
3 u |
The difference in the age between David and his uncle at first and in the end remains the same.
Difference in the age between David and his uncle
= 4 u - 1 u
= 3 u
3 u = 30
1 u = 30 ÷ 3 = 10
The increase in age of David and his uncle remains the same.
Number of years' time so David's uncle will be 4 times as old as David
= 10 - 4
= 6
Answer(s): 6
