Abi has 30% as many stamps as Erika. Erika has 110% as many stamps as Elyse. If Erika gives 55 stamps to Elyse, both will then have an equal number of stamps. Find the average number of stamps the three of them have.

Abi	Erika	Elyse
3x11	10x11
	11x10	10x10
33 u	110 u	100 u

30% = ³⁰₁₀₀ = ³₁₀
110% = ¹¹⁰₁₀₀= ¹¹₁₀

The number of stamps that Abi has is repeated.  Make the number of stamps that Abi has the same. LCM of 10 and 11 is 110.

	Erika	Elyse	Total
Before	110 u	100 u	210 u
Change	- 5 u	+ 5 u
After	105 u	105 u	210 u

Total number of stamps that Erika and Elyse have
= 110 u + 100 u
= 210 u

After Erika gives to Elyse, both of them will have the same number of stamps. 

The total number of stamps that Erika and Elyse have remains unchanged.

Number of stamps that each of them will have
= 210 u ÷ 2
= 105 u

Number of stamps that Erika gives to Elyse
= 110 u - 105 u
= 5 u

5 u = 55

1 u = 55 ÷ 5 = 11

Total number of stamps that three of them have
= 210 u + 33 u
= 243 u

Average number of stamps that each of them have
= 243 u ÷ 3
= 81 u
= 81 x 11
= 891

Answer(s): 891