Gwen has 30% as many stamps as Emily. Emily has 140% as many stamps as Rachel. If Emily gives 110 stamps to Rachel, both will then have an equal number of stamps. Find the average number of stamps the three of them have.

Gwen	Emily	Rachel
3x7	10x7
	7x10	5x10
21 u	70 u	50 u

30% = ³⁰₁₀₀ = ³₁₀
140% = ¹⁴⁰₁₀₀= ⁷₅

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

	Emily	Rachel	Total
Before	70 u	50 u	120 u
Change	- 10 u	+ 10 u
After	60 u	60 u	120 u

Total number of stamps that Emily and Rachel have
= 70 u + 50 u
= 120 u

After Emily gives to Rachel, both of them will have the same number of stamps. 

The total number of stamps that Emily and Rachel have remains unchanged.

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

Number of stamps that Emily gives to Rachel
= 70 u - 60 u
= 10 u

10 u = 110

1 u = 110 ÷ 10 = 11

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

Average number of stamps that each of them have
= 141 u ÷ 3
= 47 u
= 47 x 11
= 517

Answer(s): 517