Anna has 30% as many erasers as Nicole. Nicole has 140% as many erasers as Gillian. If Nicole gives 90 erasers to Gillian, both will then have an equal number of erasers. Find the average number of erasers the three of them have.

Anna	Nicole	Gillian
3x7	10x7
	7x10	5x10
21 u	70 u	50 u

30% = ³⁰₁₀₀ = ³₁₀
140% = ¹⁴⁰₁₀₀= ⁷₅

The number of erasers that Anna has is repeated.  Make the number of erasers that Anna has the same. LCM of 10 and 7 is 70.

	Nicole	Gillian	Total
Before	70 u	50 u	120 u
Change	- 10 u	+ 10 u
After	60 u	60 u	120 u

Total number of erasers that Nicole and Gillian have
= 70 u + 50 u
= 120 u

After Nicole gives to Gillian, both of them will have the same number of erasers. 

The total number of erasers that Nicole and Gillian have remains unchanged.

Number of erasers that each of them will have
= 120 u ÷ 2
= 60 u

Number of erasers that Nicole gives to Gillian
= 70 u - 60 u
= 10 u

10 u = 90

1 u = 90 ÷ 10 = 9

Total number of erasers that three of them have
= 120 u + 21 u
= 141 u

Average number of erasers that each of them have
= 141 u ÷ 3
= 47 u
= 47 x 9
= 423

Answer(s): 423