Winnie and Hilda collected cards. Winnie gave 50% of her cards to Hilda and as a result, Hilda's cards increased by 30%. If Winnie had 18 cards left, find the number of cards Hilda should give to Winnie in the end so that both had an equal number of cards.

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

3 u = 18

1 u = 18 ÷ 3 = 6

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

Number of cards that Hilda should give to Winnie so that both had an equal number of cards in the end
= 10 u ÷ 2
= 5 u
= 5 x 6
= 30

Answer(s): 30