<em>n=650. </em>The customer made 650 calls within the month.
Step-by-step explanation:
To solve this problem we can set it up as the equation 0.05n+18=50.5.
The reasoning of doing is because adding the monthly fee and then the amount of calls (n) times 0.05 will give us the value of n in the equation .
First we want to get rid of 18 so subtract 18 from both sides to then get 0.05n=32.5. Next we want to isolate n by dividing 0.05 on both sides of the equation which will then give us the new equation n=650.
