a cellular phone company offers a contract for which the cost C, in dollars, of t minutes of telephoning is given C=0.25(t-500)+80.95, where it is assumed that t=500 minutes. What times will keep cost between $123.45 and $146.95?

Question

a cellular phone company offers a contract for which the cost C, in dollars, of t minutes of telephoning is given C=0.25(t-500)+80.95, where it is assumed that t>=500 minutes. What times will keep cost between $123.45 and $146.95?

bobpursley · Answer

put cost in for each of those amounts, and solve for t in each case.