When Mr Archie is 40 years old, his child is 6 years old. In how many years will he be 3 times as old as his child?
|
Mr Archie |
His child |
Difference |
Before |
40 |
6 |
34 |
Change |
+ ? |
+ ? |
|
After |
3 u |
1 u |
2 u |
The difference in the age between Mr Archie and his child at first and in the end remains the same.
Difference in the age between Mr Archie and his child
= 3 u - 1 u
= 2 u
2 u = 40 - 6
2 u = 34
1 u = 34 ÷ 2 = 17
Number of years' time so Mr Archie will be 3 times as old as his child
= 17 - 6
= 11
Answer(s): 11