Roshel has 30% as many marbles as Zoe. Zoe has 110% as many marbles as Wendy. If Zoe gives 40 marbles to Wendy, both will then have an equal number of marbles. Find the average number of marbles the three of them have.

Roshel	Zoe	Wendy
3x11	10x11
	11x10	10x10
33 u	110 u	100 u

30% = ³⁰₁₀₀ = ³₁₀
110% = ¹¹⁰₁₀₀= ¹¹₁₀

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

	Zoe	Wendy	Total
Before	110 u	100 u	210 u
Change	- 5 u	+ 5 u
After	105 u	105 u	210 u

Total number of marbles that Zoe and Wendy have
= 110 u + 100 u
= 210 u

After Zoe gives to Wendy, both of them will have the same number of marbles. 

The total number of marbles that Zoe and Wendy have remains unchanged.

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

Number of marbles that Zoe gives to Wendy
= 110 u - 105 u
= 5 u

5 u = 40

1 u = 40 ÷ 5 = 8

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

Average number of marbles that each of them have
= 243 u ÷ 3
= 81 u
= 81 x 8
= 648

Answer(s): 648