Eric and Zane shared some stamps in the ratio of 5 : 7. After both each gave away 54 stamps to their brother, the ratio of the number of stamps Eric had to the total number of stamps left was 1 : 6. How many stamps did the two boys have at first?

	Eric	Zane	Difference
Before	5x2 = 10 u	7x2 = 14 u	2x2 = 4 u
Change	- 54	- 54
After	1x1 = 1 u	5x1 = 5 u	4x1 = 4 u

Number of stamps that Eric and Zane each gave to their brother is the same.

The difference in the number of stamps at first and in the end between Eric and Zane remains unchanged.  Make the difference in the number of stamps the same.  LCM of 2 and 4 is 4.

Number of stamps that Eric gave to their brother
= 10 u - 1 u
= 9 u

9 u = 54

1 u = 54 ÷ 9 = 6

Number of stamps that the two boys had at first
= 10 u + 14 u
= 24 u
= 24 x 6
= 144

Answer(s): 144