Answer:
$720
Explanation:
3 (yd³) per minute per worker.
4*3=12 yd³ per minute in total.
12*60 = 720 yd³ per hour.
8920 yd³ ÷ 720 yd³ = 12.388889 hours of work.
15$ a worker/hour x 4 workers = $60 per hour in total. Since there are only 12 whole hours in 12.388889, $60/hour x 12 full hours = $720 for all work done.