In May, Erika and Charlie had stamps in the ratio 5 : 2. In June, each of them gave away the same number of stamps. Erika then had five times as many stamps as Charlie.

1. Find the ratio of the number of stamps Charlie had in May to the number of stamps he had in June.
2. Find the ratio of the total number of stamps both had in May to the total number of stamps both had in June.

	Erika	Charlie	Difference
Before	5x4 = 20 u	2x4 = 8 u	3x4 = 12 u
Change	- 5 u	- 5 u
After	5x3 = 15 u	1x3 = 3 u	4x3 = 12 u

(a)
Since Erika and Charlie gave away the same number of stamps, the difference in the number of stamps between Erika and Charlie at first and in the end remains the same.

Make the difference in the number of stamps at first and in the end the same. LCM of 3 and 4 is 12.

Charlie's stamps in May : Charlie's stamps in June
8 : 3

(b)
Total number of stamps in May
= 20 u + 8 u
= 28 u

Total number of stamps in June
= 15 u + 3 u
= 18 u

Total stamps in May : Total stamps in June
28 : 18 _(÷2)
14 : 9 

Answer(s): (a) 8 : 3; (b) 14 : 9