Ethan's uncle is 7 times as old as him. His uncle will be 40 years old in 12 years' time. In how many years' time will Ethan's age be 60% that of his uncle's?
|
Ethan's uncle |
Ethan |
Difference |
Before (now) |
7x1 = 7 u |
1x1 = 1 u |
6x1 = 6 u |
Change 1 |
+ 12 |
+ 12 |
|
After 1 |
40 |
|
|
Change 2 |
+ ? |
+ ? |
|
After 2 |
5x3 = 15 u |
3x3 = 9 u |
2x3 = 6 u |
60% =
60100 =
35 Ethan's uncle : Ethan = 5 : 3
The difference in age between Ethan's uncle and Ethan always remains the same. Make the difference in age between Ethan's uncle and Ethan the same. LCM of 6 and 2 is 6.
7 u + 12 = 40
7 u = 40 - 12
7 u = 28
1 u = 28 ÷ 7 = 4
Number of years' time when Ethan's age will be 60% that of his uncle's
= 15 u - 40
= 15 x 4 - 40
= 60 - 40
= 20
Answer(s): 20