Sarah has 30% as many marbles as Tiffany. Tiffany has 110% as many marbles as Kylie. If Tiffany gives 45 marbles to Kylie, both will then have an equal number of marbles. Find the average number of marbles the three of them have.

Sarah	Tiffany	Kylie
3x11	10x11
	11x10	10x10
33 u	110 u	100 u

30% = ³⁰₁₀₀ = ³₁₀
110% = ¹¹⁰₁₀₀= ¹¹₁₀

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

	Tiffany	Kylie	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 Tiffany and Kylie have
= 110 u + 100 u
= 210 u

After Tiffany gives to Kylie, both of them will have the same number of marbles. 

The total number of marbles that Tiffany and Kylie have remains unchanged.

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

Number of marbles that Tiffany gives to Kylie
= 110 u - 105 u
= 5 u

5 u = 45

1 u = 45 ÷ 5 = 9

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 9
= 729

Answer(s): 729