Mr Jack is 2 times as old as his cousin, Mark. 12 years ago, the ratio in the age of Mr Jack and Mark was 7 : 2. Find Mark's current age.
| |
Mr Jack |
Mark |
Difference |
| Before |
7x1 =
7 u |
2x1 =
2 u |
5x1 =
5 u |
| Change |
+ 12 |
+ 12 |
|
| After |
2x5 =
10 u |
1x5 =
5 u |
1x5 =
5 u |
The difference in the age of Mr Jack and Mark at first and in the end remains unchanged. Make the difference in age the same. LCM of 5 and 1 is 5.
The increase in the age of Mr Jack and Mark is the same.
Increase in Mark's age
= 5 u - 2 u
= 3 u
3 u = 12
1 u = 12 ÷ 3 = 4
Mark's current age
= 5 u
= 5 x 4
= 20
Answer(s): 20
