Riordan, Eric and Chester collected stamps in the ratio of 11 : 6 : 8. After Chester gave ⁴₅ to Riordan and Eric, Chester had 565 less stamps than Riordan. The number of stamps that Eric had increased by 75%. How many stamps did Riordan and Chester have in the end?

	Riordan	Eric	Chester
Before	11 u	6 u	8 u
Change	+ 1.9 u	+ 4.5 u	- 6.4 u
After	12.9 u	10.5 u	1.6 u

Number of stamps that Chester gave to Riordan and Eric
= ⁴₅ x 8 u
= 6.4 u

Number of stamps that Eric received from Chester
= ⁷⁵₁₀₀ x 6 u
= 4.5 u

Number of stamps that Riordan received from Chester
= 6.4 u - 4.5 u
= 1.9 u

Number of less stamps that Chester had less than Riordan
= 12.9 u - 1.6 u 
= 11.3 u

11.3 u = 565

1 u = 565 ÷ 11.3 = 50

Number of stamps that Riordan and Chester had
= 12.9 u + 1.6 u
= 14.5 u
= 14.5 x 50
= 725

Answer(s): 725