Five years ago, Seth's age was 20% of Ian's age. Nine years from their current age, Seth's age will be 37.5% of Ian's age. How many years is Ian older than Seth?
| |
Seth |
Ian |
Difference |
| Before |
1x5 =
5 u |
5x5 =
25 u |
4x5 =
20 u |
| Change |
+ 5
+ 9 |
+ 5
+ 9 |
|
| After |
3x4 =
12 u |
8x4 =
32 u |
5x4 =
20 u |
20% =
20100 =
15 37.5% =
3751000 =
38The difference in the ages between Seth and Ian remains unchanged. Make the difference the same. LCM of 4 and 5 is 20.
Increase in Seth's age
= 12 u - 5 u
= 7 u
7 u = 5 + 9
7 u = 14
1 u = 14 ÷ 7 = 2
Number of years that Ian is older than Seth
= 25 u - 5 u
= 20 u
= 20 x 2
= 40
Answer(s): 40
