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Question 1081896: For her phone service, Ivanna pays a monthly fee of $20, and she pays an additional $0.04 per minute of use. The least she has been charged in a month is $79.36. What are the possible numbers of minutes she has used her phone in a month?
Use m for the number of minutes, and solve your inequality for m.
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! she pays 20 dollars plus .04 * x where x is the number of minutes she consumed.
if she has been charged 79.36, then take 20 off of that and she has been charged 59.36 for minutes of use.
divide 59.36 by .04 and she has been on the phone for 1484 minutes.
your equation is c = 20 + .04 * x
c is the total cost
x is the number of minutes.
since c is 79.36, the formula becomes 79.36 = 20 + .04 * x
subtract 20 from both sides of the equation to get 59.36 = .-04 * x
divide both sides of the equation by .04 to get 59.36 / .04 = x
solve for x to get x = 59.36 / .04 = 1484 minutes.
1484 * .04 + 20 = 79.36
solution looks good.
let x = m and you get the same solution.
c = 20 + .04 * m
79.36 = 20 + .04 * m
59.36 = .04 * m
m = 59.36 / .04 = 1484
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