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

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

3 u = 36

1 u = 36 ÷ 3 = 12

Number of cards that Jen had more than Penelope in the end
= 13 u - 3 u
= 10 u

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

Answer(s): 60