Penelope has 30% as many marbles as Rachel. Rachel has 140% as many marbles as Irene. If Rachel gives 50 marbles to Irene, both will then have an equal number of marbles. Find the average number of marbles the three of them have.

Penelope	Rachel	Irene
3x7	10x7
	7x10	5x10
21 u	70 u	50 u

30% = ³⁰₁₀₀ = ³₁₀
140% = ¹⁴⁰₁₀₀= ⁷₅

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

	Rachel	Irene	Total
Before	70 u	50 u	120 u
Change	- 10 u	+ 10 u
After	60 u	60 u	120 u

Total number of marbles that Rachel and Irene have
= 70 u + 50 u
= 120 u

After Rachel gives to Irene, both of them will have the same number of marbles. 

The total number of marbles that Rachel and Irene have remains unchanged.

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

Number of marbles that Rachel gives to Irene
= 70 u - 60 u
= 10 u

10 u = 50

1 u = 50 ÷ 10 = 5

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

Average number of marbles that each of them have
= 141 u ÷ 3
= 47 u
= 47 x 5
= 235

Answer(s): 235