Usha's father is 4 times as old as her. Usha will be 19 years old in 9 years' time. In how many years' time will Usha's age be 60% that of her father's?
| |
Usha's father |
Usha |
Difference |
Before
(now) |
4x2 =
8 u |
1x2 =
2 u |
3x2 =
6 u |
| Change 1 |
+ 9 |
+ 9 |
|
| After 1 |
|
19 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
5x3 =
15 u |
3x3 =
9 u |
2x3 =
6 u |
60% =
60100 =
35 Usha's father : Usha = 5 : 3
The difference in age between Usha's father and Usha always remains the same. Make the difference in age between Usha's father and Usha the same. LCM of 3 and 2 is 6.
2 u + 9 = 19
2 u = 19 - 9
2 u = 10
1 u = 10 ÷ 2 = 5
Number of years' time when Usha's age will be 60% that of her father's
= 15 u - 49
= 15 x 5 - 49
= 75 - 49
= 26
Answer(s): 26
