Marion has 30% as many stamps as Usha. Usha has 110% as many stamps as Kylie. If Usha gives 50 stamps to Kylie, both will then have an equal number of stamps. Find the average number of stamps the three of them have.

Marion	Usha	Kylie
3x11	10x11
	11x10	10x10
33 u	110 u	100 u

30% = ³⁰₁₀₀ = ³₁₀
110% = ¹¹⁰₁₀₀= ¹¹₁₀

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

	Usha	Kylie	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 Usha and Kylie have
= 110 u + 100 u
= 210 u

After Usha gives to Kylie, both of them will have the same number of stamps. 

The total number of stamps that Usha and Kylie have remains unchanged.

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

Number of stamps that Usha gives to Kylie
= 110 u - 105 u
= 5 u

5 u = 50

1 u = 50 ÷ 5 = 10

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 10
= 810

Answer(s): 810