John is 4 years old. His father is 32 years older than him. In how many years will John's father be 3 times as old as John?
| |
His father |
John |
Difference |
| Before |
36 |
4 |
32 |
| Change |
+ ? |
+ ? |
|
| After |
3 u |
1 u |
2 u |
The difference in the age between John and his father at first and in the end remains the same.
Difference in the age between John and his father
= 3 u - 1 u
= 2 u
2 u = 32
1 u = 32 ÷ 2 = 16
The increase in age of John and his father remains the same.
Number of years' time so John's father will be 3 times as old as John
= 16 - 4
= 12
Answer(s): 12
