Jane has 25% as many marbles as Xandra. Xandra has 130% as many marbles as Zara. If Xandra gives 72 marbles to Zara, both will then have an equal number of marbles. Find the average number of marbles the three of them have.

Jane	Xandra	Zara
1x13	4x13
	13x4	10x4
13 u	52 u	40 u

25% = ²⁵₁₀₀ = ¹₄
130% = ¹³⁰₁₀₀= ¹³₁₀

The number of marbles that Jane has is repeated.  Make the number of marbles that Jane has the same. LCM of 4 and 13 is 52.

	Xandra	Zara	Total
Before	52 u	40 u	92 u
Change	- 6 u	+ 6 u
After	46 u	46 u	92 u

Total number of marbles that Xandra and Zara have
= 52 u + 40 u
= 92 u

After Xandra gives to Zara, both of them will have the same number of marbles. 

The total number of marbles that Xandra and Zara have remains unchanged.

Number of marbles that each of them will have
= 92 u ÷ 2
= 46 u

Number of marbles that Xandra gives to Zara
= 52 u - 46 u
= 6 u

6 u = 72

1 u = 72 ÷ 6 = 12

Total number of marbles that three of them have
= 92 u + 13 u
= 105 u

Average number of marbles that each of them have
= 105 u ÷ 3
= 35 u
= 35 x 12
= 420

Answer(s): 420