#### Answer

(a) Cost for a 5 minute call:
Penny Saver \$0.415
Most Minutes \$0.503
USA Card \$0.30
(b) The cost per minute, based on a 5 minute call, is:
Penny Saver \$0.083/min
Most Minutes \$0.101/min
USA Card \$0.06/min
The best buy is the USA Card.

#### Work Step by Step

(a) To find the actual total cost, add the connection fee to the per minute charge for 5 minutes.
Penny Saver $0.39 + (5)(0.005)$ = $0.39+0.025$ = 0.415
Most Minutes $0.49 + (5)(0.0025)$ = $0.49+0.0125$ = $0.49+0.013$ = 0.503
USA Card $0.25 + (5)(0.01)$ = $0.25+0.05$ = 0.30
(b) Use the actual cost from (a) to find the unit cost.
Penny Saver $\frac{0.415}{5 min}$ = $\frac{0.415\div5}{5\div5 min}$ = $\frac{0.083}{1 min}$ = 0.083/min
Most Minutes $\frac{0.503}{5 min}$ = $\frac{0.503\div5}{5\div5 min}$ = $\frac{0.1006}{1 min}$ = 0.101/min
USA Card $\frac{0.30}{5 min}$ = $\frac{0.30\div5}{5\div5 min}$ = $\frac{0.06}{1 min}$ = 0.06/min