SOLUTION: A cellular phone company offers a contract for which the cost C, in dollars, of t minutes of telephoning is given by C=0.25 (t-400)+ 71.95, where it is assumed that t >

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Question 474893: A cellular phone company offers a contract for which the cost C, in dollars, of t minutes of telephoning is given by C=0.25 (t-400)+ 71.95, where it is assumed that t >_ 400 minutes. What times will keep costs between $112.70 and $153.20?
Answer by lwsshak3(11628) (Show Source):
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A cellular phone company offers a contract for which the cost C, in dollars, of t minutes of telephoning is given by C=0.25 (t-400)+ 71.95, where it is assumed that t >_ 400 minutes. What times will keep costs between $112.70 and $153.20?
**
112.70>0.25 (t-400)+ 71.95>153.20
subtract 71.95
40.75>.25(t-400)>81.25
Divide by .25
163.00 add 400
563 > t > 725
ans:
telephoning between 563 and 725 minutes will keep costs between $112.70 and $153.20?

SOLUTION: A cellular phone company offers a contract for which the cost C, in dollars, of t minutes of telephoning is given by C=0.25 (t-400)+ 71.95, where it is assumed that t >_ 400 minute