Betty and Joelle collected marbles. Betty gave 50% of her marbles to Joelle and as a result, Joelle's marbles increased by 30%. If Betty had 33 marbles left, find the number of marbles Joelle should give to Betty in the end so that both had an equal number of marbles.

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

3 u = 33

1 u = 33 ÷ 3 = 11

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

Number of marbles that Joelle should give to Betty so that both had an equal number of marbles in the end
= 10 u ÷ 2
= 5 u
= 5 x 11
= 55

Answer(s): 55