When Mr John is 34 years old, his child is 4 years old. In how many years will he be 3 times as old as his child?
|
Mr John |
His child |
Difference |
Before |
34 |
4 |
30 |
Change |
+ ? |
+ ? |
|
After |
3 u |
1 u |
2 u |
The difference in the age between Mr John and his child at first and in the end remains the same.
Difference in the age between Mr John and his child
= 3 u - 1 u
= 2 u
2 u = 34 - 4
2 u = 30
1 u = 30 ÷ 2 = 15
Number of years' time so Mr John will be 3 times as old as his child
= 15 - 4
= 11
Answer(s): 11