Answer:
78.5
Step-by-step explanation:
Get more specific. Don't look at days know, look at hours. Since there are 24 hours in a day, and there are 17 days, do 17*24 to get a total of 408 hours. Divide this by 2 to get 204 hours (or 8 hours 30 minutes) for each person's trip.
:)
Just like any other variable, we complete the same process

Now we can test it, let's say k=4, d=6, and c=2, let's find the value of g

OR
I think its C. (f+g)(x) = fx + gx hence just add them up