Question

A company has two electric motors that consume varying amounts of power. The power consumed by each motor is a function of the time (t in minutes) for which it runs. The cost of power (in $) to run one motor is given by the function Ca(t)=t2−2t+5. The cost of running the second motor is given by Cb(t)=3t+2. Which function gives the total cost of running both motors?