Oliver, Albert and Chung collected marbles in the ratio of 9 : 8 : 7. After Chung gave ³₅ to Oliver and Albert, Chung had 500 less marbles than Oliver. The number of marbles that Albert had increased by 5%. How many marbles did Oliver and Chung have in the end?

	Oliver	Albert	Chung
Before	9 u	8 u	7 u
Change	+ 3.8 u	+ 0.4 u	- 4.2 u
After	12.8 u	8.4 u	2.8 u

Number of marbles that Chung gave to Oliver and Albert
= ³₅ x 7 u
= 4.2 u

Number of marbles that Albert received from Chung
= ⁵₁₀₀ x 8 u
= 0.4 u

Number of marbles that Oliver received from Chung
= 4.2 u - 0.4 u
= 3.8 u

Number of less marbles that Chung had less than Oliver
= 12.8 u - 2.8 u 
= 10 u

10 u = 500

1 u = 500 ÷ 10 = 50

Number of marbles that Oliver and Chung had
= 12.8 u + 2.8 u
= 15.6 u
= 15.6 x 50
= 780

Answer(s): 780