Mrs Choy is 30 years old and her child is 6 years old now. In how many years' time will Mrs Choy be four times as old as her child?
| |
Mrs Choy |
Her child |
Difference |
| Before |
30 |
6 |
24 |
| Change |
+ ? |
+ ? |
|
| After |
4 u |
1 u |
3 u |
The difference in the age between Mrs Choy and her child remains unchanged.
Difference in their age at first
= 30 - 6
= 24
Difference in their age in the end
= 4 u - 1 u
= 3 u
3 u = 24
1 u = 24 ÷ 3 = 8
Number of years time that Mrs Choy will be four times as old as her child
= 1 u - 6
= 8 - 6
= 2
Answer(s): 2
