Owen, Brandon and Corwin collected marbles in the ratio of 9 : 8 : 9. After Corwin gave ⁴₅ to Owen and Brandon, Corwin had 400 less marbles than Owen. The number of marbles that Brandon had increased by 80%. How many marbles did Owen and Corwin have in the end?

	Owen	Brandon	Corwin
Before	9 u	8 u	9 u
Change	+ 0.8 u	+ 6.4 u	- 7.2 u
After	9.8 u	14.4 u	1.8 u

Number of marbles that Corwin gave to Owen and Brandon
= ⁴₅ x 9 u
= 7.2 u

Number of marbles that Brandon received from Corwin
= ⁸⁰₁₀₀ x 8 u
= 6.4 u

Number of marbles that Owen received from Corwin
= 7.2 u - 6.4 u
= 0.8 u

Number of less marbles that Corwin had less than Owen
= 9.8 u - 1.8 u 
= 8 u

8 u = 400

1 u = 400 ÷ 8 = 50

Number of marbles that Owen and Corwin had
= 9.8 u + 1.8 u
= 11.6 u
= 11.6 x 50
= 580

Answer(s): 580