posted by jeanette on .
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-600)+ 79.95, where it is assumed that t>=600 minutes. What times will keep costs between $119.45 and $162.70? For the costs to be between $119.45 and $162.70 , the telephoning time must be between __ minutes and __ minutes.
Set C = 119.45 and solve for t.
Set C = 162.70 and solve for t.
I think the spirit of the problem is those two values for C go in the blanks; however, technically, I think the word between would make the time for the smaller value to be 1 minute more and the time for the larger value to be 1 minute less.