Ethan, Xavier, Perry and Riordan went shopping with a total of $675. After shopping, they had a total of $128 left. Xavier spent $20. The amount Perry spent was ³₈ the amount spent by Ethan. The total amount spent by Ethan and Xavier was $283 less than the total amount spent by Perry and Riordan. How much did Ethan and Riordan spend altogether?

	Ethan	Xavier	Perry	Riordan	Total
Before					$675
Change	- 8 u	- $20	- 3 u	- ?	- $547
After					$128

Total amount that Ethan, Xavier, Perry and Riordan spent
= 675 - 128
= $547

Total amount that Ethan and Xavier spent
= 8 u + 20

Total amount that Perry and Riordan spent
= 8 u + 20 + 283
= 8 u + 303 

Total amount that Ethan, Xavier, Perry and Riordan spent
= 8 u + 20 + 8 u + 303
= 16 u + 323 

16 u + 323 = 547
16 u = 547 - 323
16 u = 224 

1 u = 224 ÷ 16 = 14

Total amount that Xavier and Perry spent
= 3 u + 20
= 3 x 14 + 20
= 42 + 20
= $62

Total amount that Ethan and Riordan spent
= 547 - 62
= $485

Answer(s): $485