Eva and Cathy collected stickers. Eva gave 60% of her stickers to Cathy and as a result, Cathy's stickers increased by 20%. If Eva had 20 stickers left, find the number of stickers Cathy should give to Eva in the end so that both had an equal number of stickers.

	Eva	Cathy	Comparing the change in Cathy's stickers
Before	5x1 = 5 u		5x3 = 15u
Change	- 3x1 = - 3 u	+ 3x1 = + 3 u	+ 1x3 = + 3 u
After	2x1 = 2 u		6x3 = 18 u

60% = ⁶⁰₁₀₀ = ³₅
20% = ²⁰₁₀₀ = ¹₅

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

2 u = 20

1 u = 20 ÷ 2 = 10

Number of stickers that Cathy had more than Eva in the end
= 18 u - 2 u
= 16 u

Number of stickers that Cathy should give to Eva so that both had an equal number of stickers in the end
= 16 u ÷ 2
= 8 u
= 8 x 10
= 80

Answer(s): 80