Cindy has 30% as many pens as Winnie. Winnie has 110% as many pens as Kimberly. If Winnie gives 30 pens to Kimberly, both will then have an equal number of pens. Find the average number of pens the three of them have.

Cindy	Winnie	Kimberly
3x11	10x11
	11x10	10x10
33 u	110 u	100 u

30% = ³⁰₁₀₀ = ³₁₀
110% = ¹¹⁰₁₀₀= ¹¹₁₀

The number of pens that Cindy has is repeated.  Make the number of pens that Cindy has the same. LCM of 10 and 11 is 110.

	Winnie	Kimberly	Total
Before	110 u	100 u	210 u
Change	- 5 u	+ 5 u
After	105 u	105 u	210 u

Total number of pens that Winnie and Kimberly have
= 110 u + 100 u
= 210 u

After Winnie gives to Kimberly, both of them will have the same number of pens. 

The total number of pens that Winnie and Kimberly have remains unchanged.

Number of pens that each of them will have
= 210 u ÷ 2
= 105 u

Number of pens that Winnie gives to Kimberly
= 110 u - 105 u
= 5 u

5 u = 30

1 u = 30 ÷ 5 = 6

Total number of pens that three of them have
= 210 u + 33 u
= 243 u

Average number of pens that each of them have
= 243 u ÷ 3
= 81 u
= 81 x 6
= 486

Answer(s): 486