Answer:
4 ft/min
Step-by-step explanation:
I'm sorry no one has helped you in 40 minutes, so let me.
Theres a fun trick when it comes to saying something 'per' something;
as you can look at the word per as a fancy word for divide.
So if I have Xylophones per Megaphone then I'm basically saying:
Xylophones divided by megaphones
So in this case its 10 feet per 2 1/2 minutes and we'd understand it as 10/2.5
Lets show this
10 ft per 2 1/2 minutes = 10/2.5 ft/min = 4 ft/min
Hope this helps :)