Eric and Mark shared some stamps in the ratio of 5 : 7. After both each gave away 52 stamps to their sister, the ratio of the number of stamps Eric had to the total number of stamps left was 1 : 5. How many stamps did the two boys have in the end?
| |
Eric |
Mark |
Difference |
| Before |
5x3 =
15 u |
7x3 =
21 u |
2x3 =
6 u |
| Change |
- 52 |
- 52 |
|
| After |
1x2 =
2 u |
4x2 =
8 u |
3x2 =
6 u |
Number of stamps that Eric and Mark each gave to their sister is the same.
The difference in the number of stamps at first and in the end between Eric and Mark remains unchanged. Make the difference in the number of stamps the same. LCM of 2 and 3 is 6.
Number of stamps that Eric gave to their sister
= 15 u - 2 u
= 13 u
13 u = 52
1 u = 52 ÷ 13 = 4
Number of stamps that the two boys had in the end
= 2 u + 8 u
= 10 u
= 10 x 4
= 40
Answer(s): 40
