John is 5 years old. His mother is 34 years older than him. In how many years will John's mother be 3 times as old as John?
| |
His mother |
John |
Difference |
| Before |
39 |
5 |
34 |
| Change |
+ ? |
+ ? |
|
| After |
3 u |
1 u |
2 u |
The difference in the age between John and his mother at first and in the end remains the same.
Difference in the age between John and his mother
= 3 u - 1 u
= 2 u
2 u = 34
1 u = 34 ÷ 2 = 17
The increase in age of John and his mother remains the same.
Number of years' time so John's mother will be 3 times as old as John
= 17 - 5
= 12
Answer(s): 12
