Mr Justin is 3 times as old as his son, Zeph. 6 years ago, the ratio in the age of Mr Justin and Zeph was 9 : 2. Find Mr Justin's current age.
| |
Mr Justin |
Zeph |
Difference |
| Before |
9x2 =
18 u |
2x2 =
4 u |
7x2 =
14 u |
| Change |
+ 6 |
+ 6 |
|
| After |
3x7 =
21 u |
1x7 =
7 u |
2x7 =
14 u |
The difference in the age of Mr Justin and Zeph 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 Justin and Zeph is the same.
Increase in Zeph's age
= 7 u - 4 u
= 3 u
3 u = 6
1 u = 6 ÷ 3 = 2
Mr Justin's current age
= 21 u
= 21 x 2
= 42
Answer(s): 42
