Hilda and Barbara collected seashells. Hilda gave 60% of her seashells to Barbara and as a result, Barbara's seashells increased by 20%. If Hilda had 10 seashells left, find the number of seashells Barbara should give to Hilda in the end so that both had an equal number of seashells.

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

2 u = 10

1 u = 10 ÷ 2 = 5

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

Number of seashells that Barbara should give to Hilda so that both had an equal number of seashells in the end
= 16 u ÷ 2
= 8 u
= 8 x 5
= 40

Answer(s): 40