Kathy and Vanessa collected marbles. Kathy gave 25% of her marbles to Vanessa and as a result, Vanessa's marbles increased by 30%. If Kathy had 36 marbles left, find the number of marbles Vanessa should give to Kathy in the end so that both had an equal number of marbles.

	Kathy	Vanessa	Comparing the change in Vanessa's marbles
Before	4x3 = 12 u		10x1 = 10u
Change	- 1x3 = - 3 u	+ 1x3 = + 3 u	+ 3x1 = + 3 u
After	3x3 = 9 u		13x1 = 13 u

25% = ²⁵₁₀₀ = ¹₄
30% = ³⁰₁₀₀ = ³₁₀

The increase in the number of marbles that Vanessa had is repeated.  Make the increase in the number of marbles that Vanessa had the same. LCM of 1 and 3 = 3

9 u = 36

1 u = 36 ÷ 9 = 4

Number of marbles that Vanessa had more than Kathy in the end
= 13 u - 9 u
= 4 u

Number of marbles that Vanessa should give to Kathy so that both had an equal number of marbles in the end
= 4 u ÷ 2
= 2 u
= 2 x 4
= 8

Answer(s): 8