Mrs Ong is 53 years old and her cousin is 15 years old now. In how many years' time will Mrs Ong be thrice as old as her cousin?
| |
Mrs Ong |
Her cousin |
Difference |
| Before |
53 |
15 |
38 |
| Change |
+ ? |
+ ? |
|
| After |
3 u |
1 u |
2 u |
The difference in the age between Mrs Ong and her cousin remains unchanged.
Difference in their age at first
= 53 - 15
= 38
Difference in their age in the end
= 3 u - 1 u
= 2 u
2 u = 38
1 u = 38 ÷ 2 = 19
Number of years time that Mrs Ong will be thrice as old as her cousin
= 1 u - 15
= 19 - 15
= 4
Answer(s): 4
