(1 point) The graph below shows the fuel consumption (in miles per gallon, mpg) of a car driving at various speeds (in miles pe mph). 30 (mpg) (mph) 58 79 88 98 100 (click on image to enlarge) (a) How much gas is used on a 500 mile trip at 40 mph? amount of gas = gallons (b) How much gas is saved by traveling 60 mph instead of 70 mph on a 300 mile trip? saved gas = gallons (c) According to this graph, what is the most fuel efficient speed to travel? most fuel efficient speed = mph