Answer: 
Step-by-step explanation:
To solve this problem you must apply the proccedure shown below:
- By definition, the perimeter of the figure is the sum of the lenght of each side. Then, you must make the addition as following:

Where
is the perimeter of the figure.
- Add the like terms, then, you obtain the following expression in simplest form:

Answer: 120 ft per 20 seconds
Step-by-step explanation:
Remember Im not always correct...