# Question: suppose the marginal cost of the 1 st hour of...

###### Question details

Suppose the marginal cost of the 1 ^{st} hour of talking
on the phone is $50, the marginal cost of the 2 ^{nd} hour
is $75, and the marginal cost of the 3 ^{rd} hour is $105.
In this case, the total cost of talking on the phone for 3 hours
is: