Actually, she worked for seven hours, so I'll solve for that.
7.20 x 3 = 21.6
6.75 x 4 = 27
21.6 + 27 = 48.6
48.6 /2 = 24.3
Her average should be $24.3 If she did work six hours, just multiply 6.75 x 3 and do what I did.
V of rec. prism = whl = 3x5x6 = 90
V of cone = 3.14 x (3)^2 (8) /3= 75.36
90 - 75.36 = 14.64
answer
14.64
