The equation you have to solve is 1.50 + (0.75 • 6). First, you solve what is in the parenthesis, 0.75 • 6 = 4.50. Now you simply add 1.50 and 4.50 to get $6, the total cost for 7 hours worth of parking.
The answer would be 1017.88 in³. Use the volume for cones ( 1/3 times pi times radius times height) so 1/3*3.14*9*12 in which would be 1017.88 in³ hope it helps!