Ivory has 30% as many stamps as Jaslyn. Jaslyn has 110% as many stamps as Penelope. If Jaslyn gives 20 stamps to Penelope, both will then have an equal number of stamps. Find the average number of stamps the three of them have.

Ivory	Jaslyn	Penelope
3x11	10x11
	11x10	10x10
33 u	110 u	100 u

30% = ³⁰₁₀₀ = ³₁₀
110% = ¹¹⁰₁₀₀= ¹¹₁₀

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

	Jaslyn	Penelope	Total
Before	110 u	100 u	210 u
Change	- 5 u	+ 5 u
After	105 u	105 u	210 u

Total number of stamps that Jaslyn and Penelope have
= 110 u + 100 u
= 210 u

After Jaslyn gives to Penelope, both of them will have the same number of stamps. 

The total number of stamps that Jaslyn and Penelope have remains unchanged.

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

Number of stamps that Jaslyn gives to Penelope
= 110 u - 105 u
= 5 u

5 u = 20

1 u = 20 ÷ 5 = 4

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

Average number of stamps that each of them have
= 243 u ÷ 3
= 81 u
= 81 x 4
= 324

Answer(s): 324