Irene's uncle is 6 times as old as her. Irene will be 16 years old in 12 years' time. In how many years' time will Irene's age be 60% that of her uncle's?
| |
Irene's uncle |
Irene |
Difference |
Before
(now) |
6x2 =
12 u |
1x2 =
2 u |
5x2 =
10 u |
| Change 1 |
+ 12 |
+ 12 |
|
| After 1 |
|
16 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
5x5 =
25 u |
3x5 =
15 u |
2x5 =
10 u |
60% =
60100 =
35 Irene's uncle : Irene = 5 : 3
The difference in age between Irene's uncle and Irene always remains the same. Make the difference in age between Irene's uncle and Irene the same. LCM of 5 and 2 is 10.
2 u + 12 = 16
2 u = 16 - 12
2 u = 4
1 u = 4 ÷ 2 = 2
Number of years' time when Irene's age will be 60% that of her uncle's
= 25 u - 36
= 25 x 2 - 36
= 50 - 36
= 14
Answer(s): 14
