deshawn's detailing is a service that details cars at the customers' homes or places of work. deshawn's cost for a basic detailing package is $40, and he charges $75 for this service. for a total price of $90, deshawn will also detail the car's engine, a service that adds an additional $20 to the total cost of the package. what is the marginal cost of adding the engine detailing to the basic detailing package?

Performance bicycle company makes steel and titanium handle bars for bicycles. it requires approximately 1 hour of labor to make one handle bar of either type. during the most recent accounting period, barr company made 7,700 steel bars and 2,300 titanium bars. setup costs amounted to $35,000. one batch of each type of bar was run each month. if a single company-wide overhead rate based on direct labor hours is used to allocate overhead costs to the two products, the amount of setup cost assigned to the steel bars will be: