David, Andy and Charles collected marbles in the ratio of 8 : 6 : 7. After Charles gave ³₅ to David and Andy, Charles had 85 less marbles than David. The number of marbles that Andy had increased by 15%. How many marbles did David and Charles have in the end?

	David	Andy	Charles
Before	8 u	6 u	7 u
Change	+ 3.3 u	+ 0.9 u	- 4.2 u
After	11.3 u	6.9 u	2.8 u

Number of marbles that Charles gave to David and Andy
= ³₅ x 7 u
= 4.2 u

Number of marbles that Andy received from Charles
= ¹⁵₁₀₀ x 6 u
= 0.9 u

Number of marbles that David received from Charles
= 4.2 u - 0.9 u
= 3.3 u

Number of less marbles that Charles had less than David
= 11.3 u - 2.8 u 
= 8.5 u

8.5 u = 85

1 u = 85 ÷ 8.5 = 10

Number of marbles that David and Charles had
= 11.3 u + 2.8 u
= 14.1 u
= 14.1 x 10
= 141

Answer(s): 141