Oh thats easy. It's a piece of cake. Just use your calculator
Standard: x=4
implicit: x-4=0
243 - 167 =76
The difference is 76g.
You just need to find the difference between both snacks
H + c = 605
c = h + 55
h + h + 55 = 605
2h + 55 = 605
2h = 605 - 55
2h = 550
h = 550/2
h = 275 <== there were 275 hamburgers sold on Friday
c = h + 55
c = 275 + 55
C = 330...there were 330 cheeseburgers sold on Friday