Answer:
100 local calls
Explanation:
You want to know the number of local calls Jennifer made when her telephone bill for $63.50 includes a $30 monthly charge, $18.50 in long distance charges, and local calls at $0.15 each.
Total bill
For n local calls, Jennifer's bill is ...
total bill = monthly charge + long distance charge + $0.15n
Filling in the given values, we have ...
63.50 = 30 +18.50 +0.15n
15.00 = 0.15n . . . . . . . subtract 48.50
100 = n . . . . . . . . divide by 0.15
Jennifer made 100 local calls.