Answer:
c = 40d+20
Step-by-step explanation:
He has to pay 20 dollars and that can't multiply so the forty has to multiply and it would have to be by d because c is the total cost
Step-by-step explanation:

It can be viewed different to what is more accurate depending on the relation of this question to another.
Answer:
the answer is c for Friday and 6 3/12 hours for them both combined
Step-by-step explanation:
because 3 5/12 is closest to 3 1/2=3 6/12
for fir day and Saturday day combined it would be 6 3/12
because 5/6 is 10/12 and 5/12 + 10/12 is 15/12 which is also 1 3/12
so add 3 +2=5 and then add the fraction 1 3/12 which would be 6 3/12 hours