Answer:
16 hours.
Explanation:
Let x represent number of hours.
We have been given that a moving company charges $800 plus $16 per hour. The total cost of the company moving for x hours would be
.
Another moving company charges $720 plus $21 per hour. The total cost of the company moving for x hours would be
.
Now, we will equate both expression to solve for x.
Therefore, at 16 hours the amount charged by both companies will be same.