Webwork 11 - problem 11

Does anyone know how to do problem 11?

Can you be more specific? What about the problem do you get, what part do you not get?

You have to label what those numbers represent. On a side note, the last question f'(225) = 1.2, I'm pretty sure I know the meaning of this statement, but I am unable to express what I mean to WebWork without it getting angry at me. I interpret this statement as saying that for 225 gallons of Ice Cream, you need to spend $1.2 dollars per gallon.

I had the same problem with #11 too. Webwork doesn't seem to accept any statement that I input for the 4 blanks for Question #11.

i got it now. try inputting the actual word instead of units. ex: second(s) or minute(s).