Erika and Xuan collected erasers. Erika gave 50% of her erasers to Xuan and as a result, Xuan's erasers increased by 30%. If Erika had 36 erasers left, find the number of erasers Xuan should give to Erika in the end so that both had an equal number of erasers.

	Erika	Xuan	Comparing the change in Xuan's erasers
Before	2x3 = 6 u		10x1 = 10u
Change	- 1x3 = - 3 u	+ 1x3 = + 3 u	+ 3x1 = + 3 u
After	1x3 = 3 u		13x1 = 13 u

50% = ⁵⁰₁₀₀ = ¹₂
30% = ³⁰₁₀₀ = ³₁₀

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

3 u = 36

1 u = 36 ÷ 3 = 12

Number of erasers that Xuan had more than Erika in the end
= 13 u - 3 u
= 10 u

Number of erasers that Xuan should give to Erika so that both had an equal number of erasers in the end
= 10 u ÷ 2
= 5 u
= 5 x 12
= 60

Answer(s): 60