Mark, Glen, Sean and Ethan went shopping with a total of $977. After shopping, they had a total of $186 left. Glen spent $50. The amount Sean spent was ⁴₇ the amount spent by Mark. The total amount spent by Mark and Glen was $327 less than the total amount spent by Sean and Ethan. How much did Mark and Ethan spend altogether?

	Mark	Glen	Sean	Ethan	Total
Before					$977
Change	- 7 u	- $50	- 4 u	- ?	- $791
After					$186

Total amount that Mark, Glen, Sean and Ethan spent
= 977 - 186
= $791

Total amount that Mark and Glen spent
= 7 u + 50

Total amount that Sean and Ethan spent
= 7 u + 50 + 327
= 7 u + 377 

Total amount that Mark, Glen, Sean and Ethan spent
= 7 u + 50 + 7 u + 377
= 14 u + 427 

14 u + 427 = 791
14 u = 791 - 427
14 u = 364 

1 u = 364 ÷ 14 = 26

Total amount that Glen and Sean spent
= 4 u + 50
= 4 x 26 + 50
= 104 + 50
= $154

Total amount that Mark and Ethan spent
= 791 - 154
= $637

Answer(s): $637