Mrs Kong is 63 years old and her child is 12 years old now. In how many years' time will Mrs Kong be four times as old as her child?
| |
Mrs Kong |
Her child |
Difference |
| Before |
63 |
12 |
51 |
| Change |
+ ? |
+ ? |
|
| After |
4 u |
1 u |
3 u |
The difference in the age between Mrs Kong and her child remains unchanged.
Difference in their age at first
= 63 - 12
= 51
Difference in their age in the end
= 4 u - 1 u
= 3 u
3 u = 51
1 u = 51 ÷ 3 = 17
Number of years time that Mrs Kong will be four times as old as her child
= 1 u - 12
= 17 - 12
= 5
Answer(s): 5
