SOLUTION: a cellular phone company offers a contract for which the cost of C, in dollars, of t minutes of telephoning is given by C=0.25(t-600)+ 55.95 where it is asumed that t>600 minutes.

Algebra ->  Finance -> SOLUTION: a cellular phone company offers a contract for which the cost of C, in dollars, of t minutes of telephoning is given by C=0.25(t-600)+ 55.95 where it is asumed that t>600 minutes.      Log On


   

Question 147825: a cellular phone company offers a contract for which the cost of C, in dollars, of t minutes of telephoning is given by C=0.25(t-600)+ 55.95 where it is asumed that t>600 minutes. What times will keep cost between $105.95 and $119.70?
For the cost to be between $105.95 and $119.70 the telephoning time must be between ?? minutes and ?? minutes.

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Solve the cost equation for those two dollar amounts to find the corresponding times.
1.0.25%28t%5B1%5D-600%29%2B+55.95=105.95
0.25%28t%5B1%5D-600%29=50
t%5B1%5D-600=200
t%5B1%5D=800
2.0.25%28t%5B2%5D-600%29%2B+55.95=119.70
0.25%28t%5B2%5D-600%29=63.75
t%5B2%5D-600=255
t%5B2%5D=855
For the cost to be between $105.95 and $119.70 the telephoning time must be between highlight%28800%29 minutes and highlight%28855%29 minutes.