The number of minutes for which Keith was billed = 97
Step-by-step explanation:
Step 1:
It is given that Keith pays a fixed fee of 3$ a month and 11 cents per minute for the number of minutes used.
Total cost = Fixed cost + Per minute cost
If x represents the number of minutes consumed in a month then we can compute the total cost using the below equation:
Total cost = 3$ + 0.11 * x
Step 2:
The total cost is 13.67$
Substituting in the equation we get
13.67 = 3 + 0.11 * x
x = 10.67 / 0.11 = 97 minutes
Step 3:
Answer:
The number of minutes for which Keith was billed = 97
