Diana and Ivory collected buttons. Diana gave 30% of her buttons to Ivory and as a result, Ivory's buttons increased by 25%. If Diana had 35 buttons left, find the number of buttons Ivory should give to Diana in the end so that both had an equal number of buttons.

	Diana	Ivory	Comparing the change in Ivory's buttons
Before	10x1 = 10 u		4x3 = 12u
Change	- 3x1 = - 3 u	+ 3x1 = + 3 u	+ 1x3 = + 3 u
After	7x1 = 7 u		5x3 = 15 u

30% = ³⁰₁₀₀ = ³₁₀
25% = ²⁵₁₀₀ = ¹₄

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

7 u = 35

1 u = 35 ÷ 7 = 5

Number of buttons that Ivory had more than Diana in the end
= 15 u - 7 u
= 8 u

Number of buttons that Ivory should give to Diana so that both had an equal number of buttons in the end
= 8 u ÷ 2
= 4 u
= 4 x 5
= 20

Answer(s): 20