For his long distance phone service, David pays a $3 monthly fee plus 11 cents per minute. Last month, David's long

distance bill was $23.57. For how many minutes was David billed?

187 minutes

Step-by-step explanation:

Let the total bill be represented by b (x), where x is the number of minutes used.

Then b (x) = $3.00 + ($0.11/mile) x.

If David was billed $23.57, for how many minutes was he billed? Set this equation = to $23.57 and solve for x:

$23.57 = $3.00 + ($0.11/min) x, or

$20.57 = ($0.11/min) x.

To find x, divide both sides by $0.11/min:

x = $20.57 / ($0.11/min) = 187 minutes