Oliver, Warren and Charles collected marbles in the ratio of 7 : 5 : 7. After Charles gave ³₁₀ to Oliver and Warren, Charles had 66 less marbles than Oliver. The number of marbles that Warren had increased by 40%. How many marbles did Oliver and Charles have in the end?

	Oliver	Warren	Charles
Before	7 u	5 u	7 u
Change	+ 0.1 u	+ 2 u	- 2.1 u
After	7.1 u	7 u	4.9 u

Number of marbles that Charles gave to Oliver and Warren
= ³₁₀ x 7 u
= 2.1 u

Number of marbles that Warren received from Charles
= ⁴⁰₁₀₀ x 5 u
= 2 u

Number of marbles that Oliver received from Charles
= 2.1 u - 2 u
= 0.1 u

Number of less marbles that Charles had less than Oliver
= 7.1 u - 4.9 u 
= 2.2 u

2.2 u = 66

1 u = 66 ÷ 2.2 = 30

Number of marbles that Oliver and Charles had
= 7.1 u + 4.9 u
= 12 u
= 12 x 30
= 360

Answer(s): 360