Usha's uncle is 8 times as old as her. Usha will be 11 years old in 7 years' time. In how many years' time will Usha's age be 60% that of her uncle's?
| |
Usha's uncle |
Usha |
Difference |
Before
(now) |
8x2 =
16 u |
1x2 =
2 u |
7x2 =
14 u |
| Change 1 |
+ 7 |
+ 7 |
|
| After 1 |
|
11 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
5x7 =
35 u |
3x7 =
21 u |
2x7 =
14 u |
60% =
60100 =
35 Usha's uncle : Usha = 5 : 3
The difference in age between Usha's uncle and Usha always remains the same. Make the difference in age between Usha's uncle and Usha the same. LCM of 7 and 2 is 14.
2 u + 7 = 11
2 u = 11 - 7
2 u = 4
1 u = 4 ÷ 2 = 2
Number of years' time when Usha's age will be 60% that of her uncle's
= 35 u - 39
= 35 x 2 - 39
= 70 - 39
= 31
Answer(s): 31
