Cindy has 30% as many erasers as Joelle. Joelle has 140% as many erasers as Linda. If Joelle gives 120 erasers to Linda, both will then have an equal number of erasers. Find the average number of erasers the three of them have.

Cindy	Joelle	Linda
3x7	10x7
	7x10	5x10
21 u	70 u	50 u

30% = ³⁰₁₀₀ = ³₁₀
140% = ¹⁴⁰₁₀₀= ⁷₅

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

	Joelle	Linda	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 Joelle and Linda have
= 70 u + 50 u
= 120 u

After Joelle gives to Linda, both of them will have the same number of erasers. 

The total number of erasers that Joelle and Linda have remains unchanged.

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

Number of erasers that Joelle gives to Linda
= 70 u - 60 u
= 10 u

10 u = 120

1 u = 120 ÷ 10 = 12

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 12
= 564

Answer(s): 564