Lynn, Tina and Fanny had a total of 57 stamps. The ratio of Tina's stamps to Fanny's stamps was at first 4 : 5. After Lynn and Tina each gave half of their stamps away, the 3 children had 36 stamps left. How many stamps did Lynn and Fanny have at first?
| |
Lynn |
Tina |
Fanny |
Total |
| Before |
2 p |
4 u |
5 u |
57 |
| Change |
- 1 p |
- 2 u |
|
- 21 |
| After |
1 p |
2 u |
5 u |
36 |
Number of stamps that Lynn and Tina gave away
= 57 - 36
= 21
1 p + 2 u = 21
1 p = 21 - 2 u --- (1)
1 p + 2 u + 5 u = 36
1 p + 7 u = 36
1 p = 36 - 7 u --- (2)
(1) = (2)
21 - 2 u = 36 - 7 u
7 u - 2 u = 36 - 21
5 u = 15
1 u = 15 ÷ 5 = 3
From (1)
1 p = 21 - 2 u
1 p = 21 - 2 x 3
1 p = 21 - 6 = 15
Number of stamps that Lynn and Fanny had at first
= 2 p + 5 u
= 2 x 15 + 5 x 3
= 30 + 15
= 45
Answer(s): 45
