Kathy has 30% as many erasers as Cindy. Cindy has 110% as many erasers as Gabby. If Cindy gives 35 erasers to Gabby, both will then have an equal number of erasers. Find the average number of erasers the three of them have.

Kathy	Cindy	Gabby
3x11	10x11
	11x10	10x10
33 u	110 u	100 u

30% = ³⁰₁₀₀ = ³₁₀
110% = ¹¹⁰₁₀₀= ¹¹₁₀

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

	Cindy	Gabby	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 Cindy and Gabby have
= 110 u + 100 u
= 210 u

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

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

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

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

5 u = 35

1 u = 35 ÷ 5 = 7

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 7
= 567

Answer(s): 567