When Mr Nick is 31 years old, his niece is 9 years old. In how many years will he be 3 times as old as his niece?
|
Mr Nick |
His niece |
Difference |
Before |
31 |
9 |
22 |
Change |
+ ? |
+ ? |
|
After |
3 u |
1 u |
2 u |
The difference in the age between Mr Nick and his niece at first and in the end remains the same.
Difference in the age between Mr Nick and his niece
= 3 u - 1 u
= 2 u
2 u = 31 - 9
2 u = 22
1 u = 22 ÷ 2 = 11
Number of years' time so Mr Nick will be 3 times as old as his niece
= 11 - 9
= 2
Answer(s): 2