Answer: 71.1minutes
Step-by-step explanation:
From the question, we were given monthly cost of calls and amount of call per minute.
To express the monthly cost in terms of minutes of call time will be :
Monthly cost = call per minute x f
Let minutes of call time be f
13.5= 0.19 x f
13.5 = 0.19f ....divide both sides by 0.19
f = 13.5/ 0.19
f= 71.1 minutes
