Yen and Roshel collected buttons. Yen gave 25% of her buttons to Roshel and as a result, Roshel's buttons increased by 30%. If Yen had 108 buttons left, find the number of buttons Roshel should give to Yen in the end so that both had an equal number of buttons.

	Yen	Roshel	Comparing the change in Roshel's buttons
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 buttons that Roshel had is repeated.  Make the increase in the number of buttons that Roshel had the same. LCM of 1 and 3 = 3

9 u = 108

1 u = 108 ÷ 9 = 12

Number of buttons that Roshel had more than Yen in the end
= 13 u - 9 u
= 4 u

Number of buttons that Roshel should give to Yen so that both had an equal number of buttons in the end
= 4 u ÷ 2
= 2 u
= 2 x 12
= 24

Answer(s): 24