Mr Nick is 3 times as old as his son, Billy. 9 years ago, the ratio in the age of Mr Nick and Billy was 9 : 2. Find Mr Nick's current age.
| |
Mr Nick |
Billy |
Difference |
| Before |
9x2 =
18 u |
2x2 =
4 u |
7x2 =
14 u |
| Change |
+ 9 |
+ 9 |
|
| After |
3x7 =
21 u |
1x7 =
7 u |
2x7 =
14 u |
The difference in the age of Mr Nick and Billy at first and in the end remains unchanged. Make the difference in age the same. LCM of 7 and 2 is 14.
The increase in the age of Mr Nick and Billy is the same.
Increase in Billy's age
= 7 u - 4 u
= 3 u
3 u = 9
1 u = 9 ÷ 3 = 3
Mr Nick's current age
= 21 u
= 21 x 3
= 63
Answer(s): 63
