SOLUTION: Josel buys cell-phone services from a company that charges a minimum of $20 per month. For that $20, he is allowed 100 minutes of free calls. For any calls above 100 minutes, he

Algebra ->  Graphs -> SOLUTION: Josel buys cell-phone services from a company that charges a minimum of $20 per month. For that $20, he is allowed 100 minutes of free calls. For any calls above 100 minutes, he       Log On


   



Question 1196026: Josel buys cell-phone services from a company that charges a minimum of $20 per
month. For that $20, he is allowed 100 minutes of free calls. For any calls above
100 minutes, he pays 50 cents per additional minute. Sketch a graph that describes
Josel’s monthly bill as a function of total time. Clearly label your graph.

Found 2 solutions by Theo, MathTherapy:
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
the equation would be y = 20 + .5 * (x - 100) for x > 100
with x = 100, the cost is 20.
with x = 200, the cost is 20 + .5 * 100 = 70.
here's my sketch of the graph.
y is the total cost per month.
x is the number of minutes used per month.
any minutes over 100 will kick in the incremental cost of 50 cents a minute on top of the 20 dollars for the first 100 minutes.


Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

Josel buys cell-phone services from a company that charges a minimum of $20 per
month. For that $20, he is allowed 100 minutes of free calls. For any calls above
100 minutes, he pays 50 cents per additional minute. Sketch a graph that describes
C(m) = .5(m - 100) + 20, with m ≥ 100
C(m) = .5m - 50 + 20, with m ≥ 100
Correct equation: matrix%281%2C3%2C+C%28m%29%2C+%22=%22%2C+.5m+-+30%29, with m ≥ 100
Changing the equation's variables for graphing. we get:
matrix%281%2C3%2C+y%2C+%22=%22%2C+.5x+-+30%29, with, m ≥ 100 ------ Replacing cost, based on minutes, or C(m), with y, and m (minutes) with x.
Now, YOU do the graphing.