Mrs Yeo is 51 years old and her child is 11 years old now. In how many years' time will Mrs Yeo be thrice as old as her child?
| |
Mrs Yeo |
Her child |
Difference |
| Before |
51 |
11 |
40 |
| Change |
+ ? |
+ ? |
|
| After |
3 u |
1 u |
2 u |
The difference in the age between Mrs Yeo and her child remains unchanged.
Difference in their age at first
= 51 - 11
= 40
Difference in their age in the end
= 3 u - 1 u
= 2 u
2 u = 40
1 u = 40 ÷ 2 = 20
Number of years time that Mrs Yeo will be thrice as old as her child
= 1 u - 11
= 20 - 11
= 9
Answer(s): 9
