Lynn's mother is 6 times as old as her. Lynn will be 15 years old in 9 years' time. In how many years' time will Lynn's age be 60% that of her mother's?
| |
Lynn's mother |
Lynn |
Difference |
Before
(now) |
6x2 =
12 u |
1x2 =
2 u |
5x2 =
10 u |
| Change 1 |
+ 9 |
+ 9 |
|
| After 1 |
|
15 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
5x5 =
25 u |
3x5 =
15 u |
2x5 =
10 u |
60% =
60100 =
35 Lynn's mother : Lynn = 5 : 3
The difference in age between Lynn's mother and Lynn always remains the same. Make the difference in age between Lynn's mother and Lynn the same. LCM of 5 and 2 is 10.
2 u + 9 = 15
2 u = 15 - 9
2 u = 6
1 u = 6 ÷ 2 = 3
Number of years' time when Lynn's age will be 60% that of her mother's
= 25 u - 45
= 25 x 3 - 45
= 75 - 45
= 30
Answer(s): 30
