You are choosing between two different prepaid cell phone pl

You are choosing between two different prepaid cell phone plans. The first plan charges a rate of 28 cents per minute. The second plan charges a monthly fee of $ 19.95 plus 13 cents per minute. How many minutes would you have to use in a month in order for the second plan to be preferable? You would have to use more than ______ minutes in a month.

Solution

Plan 1 : 28 cents = 0.28 dollars

C(t) = 0.28t

Plan 2 : C(t) = 19.95 + 0.13t

Plan2 to be pfefrable : 19.95 +0.13t < 0.28t

0.15t> 19.95

t > 133 minutes