Mrs Soh is 42 years old and her child is 12 years old now. In how many years' time will Mrs Soh be thrice as old as her child?
| |
Mrs Soh |
Her child |
Difference |
| Before |
42 |
12 |
30 |
| Change |
+ ? |
+ ? |
|
| After |
3 u |
1 u |
2 u |
The difference in the age between Mrs Soh and her child remains unchanged.
Difference in their age at first
= 42 - 12
= 30
Difference in their age in the end
= 3 u - 1 u
= 2 u
2 u = 30
1 u = 30 ÷ 2 = 15
Number of years time that Mrs Soh will be thrice as old as her child
= 1 u - 12
= 15 - 12
= 3
Answer(s): 3
