Gwen and Gabby collected erasers. Gwen gave 30% of her erasers to Gabby and as a result, Gabby's erasers increased by 10%. If Gwen had 70 erasers left, find the number of erasers Gabby should give to Gwen in the end so that both had an equal number of erasers.

	Gwen	Gabby	Comparing the change in Gabby's erasers
Before	10x1 = 10 u		10x3 = 30u
Change	- 3x1 = - 3 u	+ 3x1 = + 3 u	+ 1x3 = + 3 u
After	7x1 = 7 u		11x3 = 33 u

30% = ³⁰₁₀₀ = ³₁₀
10% = ¹⁰₁₀₀ = ¹₁₀

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

7 u = 70

1 u = 70 ÷ 7 = 10

Number of erasers that Gabby had more than Gwen in the end
= 33 u - 7 u
= 26 u

Number of erasers that Gabby should give to Gwen so that both had an equal number of erasers in the end
= 26 u ÷ 2
= 13 u
= 13 x 10
= 130

Answer(s): 130