10 km because you have 1 cm left over after you make 8 km with the 5cm so you just divide 8 by 4 and get 2km then add that to the 8 to get 10.
Trial and error on this one try each pair till you find negative slopes
C and D
It will be
3 4/14+2 3/14+4 6/14=9 13/14
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
