Kimberly and Tina collected cards. Kimberly gave 30% of her cards to Tina and as a result, Tina's cards increased by 25%. If Kimberly had 35 cards left, find the number of cards Tina should give to Kimberly in the end so that both had an equal number of cards.

	Kimberly	Tina	Comparing the change in Tina'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 Tina had is repeated.  Make the increase in the number of cards that Tina had the same. LCM of 3 and 1 = 3

7 u = 35

1 u = 35 ÷ 7 = 5

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

Number of cards that Tina should give to Kimberly so that both had an equal number of cards in the end
= 8 u ÷ 2
= 4 u
= 4 x 5
= 20

Answer(s): 20