Tiffany and Usha collected marbles. Tiffany gave 50% of her marbles to Usha and as a result, Usha's marbles increased by 30%. If Tiffany had 24 marbles left, find the number of marbles Usha should give to Tiffany in the end so that both had an equal number of marbles.

	Tiffany	Usha	Comparing the change in Usha's marbles
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 marbles that Usha had is repeated.  Make the increase in the number of marbles that Usha had the same. LCM of 1 and 3 = 3

3 u = 24

1 u = 24 ÷ 3 = 8

Number of marbles that Usha had more than Tiffany in the end
= 13 u - 3 u
= 10 u

Number of marbles that Usha should give to Tiffany so that both had an equal number of marbles in the end
= 10 u ÷ 2
= 5 u
= 5 x 8
= 40

Answer(s): 40