Elyse has 30% as many pens as Wendy. Wendy has 140% as many pens as Marion. If Wendy gives 110 pens to Marion, both will then have an equal number of pens. Find the average number of pens the three of them have.

Elyse	Wendy	Marion
3x7	10x7
	7x10	5x10
21 u	70 u	50 u

30% = ³⁰₁₀₀ = ³₁₀
140% = ¹⁴⁰₁₀₀= ⁷₅

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

	Wendy	Marion	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 Wendy and Marion have
= 70 u + 50 u
= 120 u

After Wendy gives to Marion, both of them will have the same number of pens. 

The total number of pens that Wendy and Marion have remains unchanged.

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

Number of pens that Wendy gives to Marion
= 70 u - 60 u
= 10 u

10 u = 110

1 u = 110 ÷ 10 = 11

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 11
= 517

Answer(s): 517