Gillian and Elyse have some notebooks in the ratio 5 : 11. Gillian has 42 less notebooks than Elyse. How many notebooks must Elyse give to Gillian so that they will have the same number of notebooks?
| |
Gillian |
Elyse |
Total |
| Before |
5 u |
11 u |
16 u |
| Change |
+ 3 u |
- 3 u |
|
After |
1x8 =
8 u |
1x8 =
8 u |
2x8 =
16 u |
The total number of notebooks remains unchanged. Make the total number of notebooks at first and in the end the same. LCM of 2 and 16 is 16.
Difference in the number of notebooks at first
= 11 u - 5 u
= 6 u
6 u = 42
1 u = 42 ÷ 6 = 7
Number of notebooks that each of them had in the end
= 16 u ÷ 2
= 8 u
Number of notebooks that Elyse must give to Gillian
= 8 u - 5 u
= 3 u
= 3 x 7
= 21
Answer(s): 21
