4. Volunteers are moving a pile of mulch at a park. The pile has 324 cubic feet of mulch. They move it using
wheelbarrows that hold 2.8 cubic feet each. The volunteers can move 11 wheelbarrows per hour. How many
cubic feet are left in the pile after the volunteers have moved mulch for 6 hours?
(1) 89.4
(3) 184.8
(2) 139.2
(4) 206.2