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

	Elyse	Sabrina	Comparing the change in Sabrina's postcards
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 postcards that Sabrina had is repeated.  Make the increase in the number of postcards that Sabrina had the same. LCM of 1 and 3 = 3

3 u = 36

1 u = 36 ÷ 3 = 12

Number of postcards that Sabrina had more than Elyse in the end
= 13 u - 3 u
= 10 u

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

Answer(s): 60