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

	Emma	Zoe	Comparing the change in Zoe's seashells
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 seashells that Zoe had is repeated.  Make the increase in the number of seashells that Zoe had the same. LCM of 3 and 1 = 3

2 u = 20

1 u = 20 ÷ 2 = 10

Number of seashells that Zoe had more than Emma in the end
= 18 u - 2 u
= 16 u

Number of seashells that Zoe should give to Emma so that both had an equal number of seashells in the end
= 16 u ÷ 2
= 8 u
= 8 x 10
= 80

Answer(s): 80