Gwen has 30% as many stamps as Linda. Linda has 140% as many stamps as Julie. If Linda gives 70 stamps to Julie, both will then have an equal number of stamps. Find the average number of stamps the three of them have.

Gwen	Linda	Julie
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.

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

After Linda gives to Julie, both of them will have the same number of stamps. 

The total number of stamps that Linda and Julie have remains unchanged.

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

Number of stamps that Linda gives to Julie
= 70 u - 60 u
= 10 u

10 u = 70

1 u = 70 ÷ 10 = 7

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 7
= 329

Answer(s): 329