Shiyun has 30% as many cards as Olivia. Olivia has 140% as many cards as Hazel. If Olivia gives 40 cards to Hazel, both will then have an equal number of cards. Find the average number of cards the three of them have.

Shiyun	Olivia	Hazel
3x7	10x7
	7x10	5x10
21 u	70 u	50 u

30% = ³⁰₁₀₀ = ³₁₀
140% = ¹⁴⁰₁₀₀= ⁷₅

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

	Olivia	Hazel	Total
Before	70 u	50 u	120 u
Change	- 10 u	+ 10 u
After	60 u	60 u	120 u

Total number of cards that Olivia and Hazel have
= 70 u + 50 u
= 120 u

After Olivia gives to Hazel, both of them will have the same number of cards. 

The total number of cards that Olivia and Hazel have remains unchanged.

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

Number of cards that Olivia gives to Hazel
= 70 u - 60 u
= 10 u

10 u = 40

1 u = 40 ÷ 10 = 4

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

Average number of cards that each of them have
= 141 u ÷ 3
= 47 u
= 47 x 4
= 188

Answer(s): 188