Charlie, Michael and Ivan have some stamps. The ratios of their stamps are as follows:

Charlie : (Charlie + Michael + Ivan) = 2 : 5
Michael : (Charlie + Ivan) = 1 : 5

Ivan has 24 stamps more than Michael. In the end, Ivan gives away all he has to Michael and Charlie so that both Michael and Charlie end up with the same number of stamps, how many stamps has Charlie received from Ivan?

Michael	Ivan	Charlie	Total
3x6		2x6	5x6
1x5	5x5		6x5
5 u	13 u	12 u	30 u

The total number of stamps is repeated.  Make the total number of stamps the same.  LCM of 5 and 6 is 30.

Number of stamps that Ivan has more than Michael
= 13 u - 5 u
= 8 u

8 u = 24

1 u = 24 ÷ 8 = 3

	Michael	Ivan	Charlie
Before	5 u	13 u	12 u
Change	+ 10 u	- 13 u	+ 3 u
After	15 u	0 u	15 u

Number of stamps that Charlie has received from Ivan
= 15 u - 12 u 
= 3 u
= 3 x 3
= 9

Answer(s): 9