Mrs Yap is 36 years old and her son is 6 years old now. In how many years' time will Mrs Yap be four times as old as her son?
| |
Mrs Yap |
Her son |
Difference |
| Before |
36 |
6 |
30 |
| Change |
+ ? |
+ ? |
|
| After |
4 u |
1 u |
3 u |
The difference in the age between Mrs Yap and her son remains unchanged.
Difference in their age at first
= 36 - 6
= 30
Difference in their age in the end
= 4 u - 1 u
= 3 u
3 u = 30
1 u = 30 ÷ 3 = 10
Number of years time that Mrs Yap will be four times as old as her son
= 1 u - 6
= 10 - 6
= 4
Answer(s): 4
