Sarah has 30% as many pens as Raeann. Raeann has 140% as many pens as Shannon. If Raeann gives 100 pens to Shannon, both will then have an equal number of pens. Find the average number of pens the three of them have.

Sarah	Raeann	Shannon
3x7	10x7
	7x10	5x10
21 u	70 u	50 u

30% = ³⁰₁₀₀ = ³₁₀
140% = ¹⁴⁰₁₀₀= ⁷₅

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

	Raeann	Shannon	Total
Before	70 u	50 u	120 u
Change	- 10 u	+ 10 u
After	60 u	60 u	120 u

Total number of pens that Raeann and Shannon have
= 70 u + 50 u
= 120 u

After Raeann gives to Shannon, both of them will have the same number of pens. 

The total number of pens that Raeann and Shannon have remains unchanged.

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

Number of pens that Raeann gives to Shannon
= 70 u - 60 u
= 10 u

10 u = 100

1 u = 100 ÷ 10 = 10

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

Average number of pens that each of them have
= 141 u ÷ 3
= 47 u
= 47 x 10
= 470

Answer(s): 470