Lucy has 30% as many erasers as Winnie. Winnie has 140% as many erasers as Nora. If Winnie gives 80 erasers to Nora, both will then have an equal number of erasers. Find the average number of erasers the three of them have.

Lucy	Winnie	Nora
3x7	10x7
	7x10	5x10
21 u	70 u	50 u

30% = ³⁰₁₀₀ = ³₁₀
140% = ¹⁴⁰₁₀₀= ⁷₅

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

	Winnie	Nora	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 Winnie and Nora have
= 70 u + 50 u
= 120 u

After Winnie gives to Nora, both of them will have the same number of erasers. 

The total number of erasers that Winnie and Nora have remains unchanged.

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

Number of erasers that Winnie gives to Nora
= 70 u - 60 u
= 10 u

10 u = 80

1 u = 80 ÷ 10 = 8

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 8
= 376

Answer(s): 376