A field cultivator is a tool that is pulled behind a tractor to work ground in a field. How long

would it take to work a 640-acre field (1 mi long and 1 mi wide) with a field cultivator that is 60

feet wide if the tractor pulling it goes 8.4 miles per hour? (Don't worry about turnaround time.

Round your answer to the nearest hundredth of an hour if necessary.) solve an

equation to answer this question. Be sure to clearly define any variable(s) used.