Answer
If the number of classes is c, cost=$15c+20$.
Work Step by Step
You can see from the values in the table that there is a \$15 charge that is assessed per class taken. You can also see from the values in the table that there is a \$20 charge that is included no matter how many classes are taken.
The cost of the classes is \$20 plus an additional \$15 for each class taken.
