Bryan and Tommy shared some stamps in the ratio of 5 : 7. After both each gave away 18 stamps to their brother, the ratio of the number of stamps Bryan had to the total number of stamps left was 1 : 6. How many stamps did the two boys have at first?
|
Bryan |
Tommy |
Difference |
Before |
5x2 = 10 u |
7x2 = 14 u |
2x2 = 4 u |
Change |
- 18 |
- 18 |
|
After |
1x1 = 1 u |
5x1 = 5 u |
4x1 = 4 u |
Number of stamps that Bryan and Tommy each gave to their brother is the same.
The difference in the number of stamps at first and in the end between Bryan and Tommy remains unchanged. Make the difference in the number of stamps the same. LCM of 2 and 4 is 4.
Number of stamps that Bryan gave to their brother
= 10 u - 1 u
= 9 u
9 u = 18
1 u = 18 ÷ 9 = 2
Number of stamps that the two boys had at first
= 10 u + 14 u
= 24 u
= 24 x 2
= 48
Answer(s): 48