Bobby is 4 years old. His uncle is 42 years older than him. In how many years will Bobby's uncle be 4 times as old as Bobby?
| |
His uncle |
Bobby |
Difference |
| Before |
46 |
4 |
42 |
| Change |
+ ? |
+ ? |
|
| After |
4 u |
1 u |
3 u |
The difference in the age between Bobby and his uncle at first and in the end remains the same.
Difference in the age between Bobby and his uncle
= 4 u - 1 u
= 3 u
3 u = 42
1 u = 42 ÷ 3 = 14
The increase in age of Bobby and his uncle remains the same.
Number of years' time so Bobby's uncle will be 4 times as old as Bobby
= 14 - 4
= 10
Answer(s): 10
