Daniel, Luis and Glen had a total of 60 stamps. The ratio of the number of stamps that Luis had to the number of stamps that Glen had was 4 : 5. After Daniel and Luis each gave away half of their stamps, the 3 children had 40 stamps left. How many stamps did Luis and Glen have at first?
| |
Daniel |
Luis |
Glen |
Total |
| Before |
2 p |
4 u |
5 u |
60 |
| Change |
- 1 p |
- 2 u |
|
- 20 |
| After |
1 p |
2 u |
5 u |
40 |
Total number of stamps that Daniel and Luis gave away
= 60 - 40
= 20
1 p + 2 u = 20 --- (1)
1 p + 2 u + 5 u = 40
1 p + 7 u = 40 --- (2)
(2) - (1)
(1 p + 7 u) - (1 p + 2 u) = 40 - 20
7 u - 2 u = 20
5 u = 20
1 u = 20 ÷ 5 = 4
Total number of stamps that Luis and Glen had at first
= 4 u + 5 u
= 9 u
= 9 x 4
= 36
Answer(s): 36
