Vanessa and Joelle collected cards. Vanessa gave 30% of her cards to Joelle and as a result, Joelle's cards increased by 25%. If Vanessa had 70 cards left, find the number of cards Joelle should give to Vanessa in the end so that both had an equal number of cards.

	Vanessa	Joelle	Comparing the change in Joelle's cards
Before	10x1 = 10 u		4x3 = 12u
Change	- 3x1 = - 3 u	+ 3x1 = + 3 u	+ 1x3 = + 3 u
After	7x1 = 7 u		5x3 = 15 u

30% = ³⁰₁₀₀ = ³₁₀
25% = ²⁵₁₀₀ = ¹₄

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

7 u = 70

1 u = 70 ÷ 7 = 10

Number of cards that Joelle had more than Vanessa in the end
= 15 u - 7 u
= 8 u

Number of cards that Joelle should give to Vanessa so that both had an equal number of cards in the end
= 8 u ÷ 2
= 4 u
= 4 x 10
= 40

Answer(s): 40