Abi has 25% as many marbles as Sarah. Sarah has 130% as many marbles as Victoria. If Sarah gives 18 marbles to Victoria, both will then have an equal number of marbles. Find the average number of marbles the three of them have.

Abi	Sarah	Victoria
1x13	4x13
	13x4	10x4
13 u	52 u	40 u

25% = ²⁵₁₀₀ = ¹₄
130% = ¹³⁰₁₀₀= ¹³₁₀

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

	Sarah	Victoria	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 Sarah and Victoria have
= 52 u + 40 u
= 92 u

After Sarah gives to Victoria, both of them will have the same number of marbles. 

The total number of marbles that Sarah and Victoria have remains unchanged.

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

Number of marbles that Sarah gives to Victoria
= 52 u - 46 u
= 6 u

6 u = 18

1 u = 18 ÷ 6 = 3

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 3
= 105

Answer(s): 105