Penelope has 30% as many erasers as Gabby. Gabby has 110% as many erasers as Xandra. If Gabby gives 55 erasers to Xandra, both will then have an equal number of erasers. Find the average number of erasers the three of them have.

Penelope	Gabby	Xandra
3x11	10x11
	11x10	10x10
33 u	110 u	100 u

30% = ³⁰₁₀₀ = ³₁₀
110% = ¹¹⁰₁₀₀= ¹¹₁₀

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

	Gabby	Xandra	Total
Before	110 u	100 u	210 u
Change	- 5 u	+ 5 u
After	105 u	105 u	210 u

Total number of erasers that Gabby and Xandra have
= 110 u + 100 u
= 210 u

After Gabby gives to Xandra, both of them will have the same number of erasers. 

The total number of erasers that Gabby and Xandra have remains unchanged.

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

Number of erasers that Gabby gives to Xandra
= 110 u - 105 u
= 5 u

5 u = 55

1 u = 55 ÷ 5 = 11

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

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

Answer(s): 891