When Mr Harry is 23 years old, his nephew is 3 years old. In how many years will he be 3 times as old as his nephew?
|
Mr Harry |
His nephew |
Difference |
Before |
23 |
3 |
20 |
Change |
+ ? |
+ ? |
|
After |
3 u |
1 u |
2 u |
The difference in the age between Mr Harry and his nephew at first and in the end remains the same.
Difference in the age between Mr Harry and his nephew
= 3 u - 1 u
= 2 u
2 u = 23 - 3
2 u = 20
1 u = 20 ÷ 2 = 10
Number of years' time so Mr Harry will be 3 times as old as his nephew
= 10 - 3
= 7
Answer(s): 7