Mrs Lim is 41 years old and her nephew is 9 years old now. In how many years' time will Mrs Lim be thrice as old as her nephew?
|
Mrs Lim |
Her nephew |
Difference |
Before |
41 |
9 |
32 |
Change |
+ ? |
+ ? |
|
After |
3 u |
1 u |
2 u |
The difference in the age between Mrs Lim and her nephew remains unchanged.
Difference in their age at first
= 41 - 9
= 32
Difference in their age in the end
= 3 u - 1 u
= 2 u
2 u = 32
1 u = 32 ÷ 2 = 16
Number of years time that Mrs Lim will be thrice as old as her nephew
= 1 u - 9
= 16 - 9
= 7
Answer(s): 7