Jane's mother is 8 times as old as her. Jane will be 12 years old in 8 years' time. In how many years' time will Jane's age be 60% that of her mother's?
| |
Jane's mother |
Jane |
Difference |
Before
(now) |
8x2 =
16 u |
1x2 =
2 u |
7x2 =
14 u |
| Change 1 |
+ 8 |
+ 8 |
|
| After 1 |
|
12 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
5x7 =
35 u |
3x7 =
21 u |
2x7 =
14 u |
60% =
60100 =
35 Jane's mother : Jane = 5 : 3
The difference in age between Jane's mother and Jane always remains the same. Make the difference in age between Jane's mother and Jane the same. LCM of 7 and 2 is 14.
2 u + 8 = 12
2 u = 12 - 8
2 u = 4
1 u = 4 ÷ 2 = 2
Number of years' time when Jane's age will be 60% that of her mother's
= 35 u - 40
= 35 x 2 - 40
= 70 - 40
= 30
Answer(s): 30
