John is 4 years old. His mother is 30 years older than him. In how many years will John's mother be 4 times as old as John?
| |
His mother |
John |
Difference |
| Before |
34 |
4 |
30 |
| Change |
+ ? |
+ ? |
|
| After |
4 u |
1 u |
3 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
= 4 u - 1 u
= 3 u
3 u = 30
1 u = 30 ÷ 3 = 10
The increase in age of John and his mother remains the same.
Number of years' time so John's mother will be 4 times as old as John
= 10 - 4
= 6
Answer(s): 6
