Seth, Sean and Charlie collected erasers in the ratio of 12 : 7 : 7. After Charlie gave ³₅ to Seth and Sean, Charlie had 508 less erasers than Seth. The number of erasers that Sean had increased by 10%. How many erasers did Seth and Charlie have in the end?

	Seth	Sean	Charlie
Before	12 u	7 u	7 u
Change	+ 3.5 u	+ 0.7 u	- 4.2 u
After	15.5 u	7.7 u	2.8 u

Number of erasers that Charlie gave to Seth and Sean
= ³₅ x 7 u
= 4.2 u

Number of erasers that Sean received from Charlie
= ¹⁰₁₀₀ x 7 u
= 0.7 u

Number of erasers that Seth received from Charlie
= 4.2 u - 0.7 u
= 3.5 u

Number of less erasers that Charlie had less than Seth
= 15.5 u - 2.8 u 
= 12.7 u

12.7 u = 508

1 u = 508 ÷ 12.7 = 40

Number of erasers that Seth and Charlie had
= 15.5 u + 2.8 u
= 18.3 u
= 18.3 x 40
= 732

Answer(s): 732