Julie and Xandra collected erasers. Julie gave 50% of her erasers to Xandra and as a result, Xandra's erasers increased by 30%. If Julie had 21 erasers left, find the number of erasers Xandra should give to Julie in the end so that both had an equal number of erasers.

	Julie	Xandra	Comparing the change in Xandra'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 Xandra had is repeated.  Make the increase in the number of erasers that Xandra had the same. LCM of 1 and 3 = 3

3 u = 21

1 u = 21 ÷ 3 = 7

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

Number of erasers that Xandra should give to Julie so that both had an equal number of erasers in the end
= 10 u ÷ 2
= 5 u
= 5 x 7
= 35

Answer(s): 35