Gillian and Sarah collected marbles. Gillian gave 60% of her marbles to Sarah and as a result, Sarah's marbles increased by 20%. If Gillian had 24 marbles left, find the number of marbles Sarah should give to Gillian in the end so that both had an equal number of marbles.

	Gillian	Sarah	Comparing the change in Sarah's marbles
Before	5x1 = 5 u		5x3 = 15u
Change	- 3x1 = - 3 u	+ 3x1 = + 3 u	+ 1x3 = + 3 u
After	2x1 = 2 u		6x3 = 18 u

60% = ⁶⁰₁₀₀ = ³₅
20% = ²⁰₁₀₀ = ¹₅

The increase in the number of marbles that Sarah had is repeated.  Make the increase in the number of marbles that Sarah had the same. LCM of 3 and 1 = 3

2 u = 24

1 u = 24 ÷ 2 = 12

Number of marbles that Sarah had more than Gillian in the end
= 18 u - 2 u
= 16 u

Number of marbles that Sarah should give to Gillian so that both had an equal number of marbles in the end
= 16 u ÷ 2
= 8 u
= 8 x 12
= 96

Answer(s): 96