Hilda has 30% as many marbles as Roshel. Roshel has 110% as many marbles as Ivory. If Roshel gives 15 marbles to Ivory, both will then have an equal number of marbles. Find the average number of marbles the three of them have.

Hilda	Roshel	Ivory
3x11	10x11
	11x10	10x10
33 u	110 u	100 u

30% = ³⁰₁₀₀ = ³₁₀
110% = ¹¹⁰₁₀₀= ¹¹₁₀

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

	Roshel	Ivory	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 Roshel and Ivory have
= 110 u + 100 u
= 210 u

After Roshel gives to Ivory, both of them will have the same number of marbles. 

The total number of marbles that Roshel and Ivory have remains unchanged.

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

Number of marbles that Roshel gives to Ivory
= 110 u - 105 u
= 5 u

5 u = 15

1 u = 15 ÷ 5 = 3

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 3
= 243

Answer(s): 243