Harry is 2 years old. His father is 18 years older than him. In how many years will Harry's father be 3 times as old as Harry?
| |
His father |
Harry |
Difference |
| Before |
20 |
2 |
18 |
| Change |
+ ? |
+ ? |
|
| After |
3 u |
1 u |
2 u |
The difference in the age between Harry and his father at first and in the end remains the same.
Difference in the age between Harry and his father
= 3 u - 1 u
= 2 u
2 u = 18
1 u = 18 ÷ 2 = 9
The increase in age of Harry and his father remains the same.
Number of years' time so Harry's father will be 3 times as old as Harry
= 9 - 2
= 7
Answer(s): 7
