Question

The phone company offers Rachel 12c per minute for her long distance calls. A discount company called Rachel and offered her long service for 1/2c per minute, but will charge a R46 monthly fee. How many minutes per month must Rachel talk on the phone to make the discount a better deal?

Answer 1

Step-by-step explanation:

x = number of minutes

the cost function (in c) of the phone company is

cp(x) = 12x

and the cost function of the discount company is

cd(x) = x/2 + 4600 (R46)

we now need to calculate for what x this becomes the same cost :

12x = x/2 + 4600

24x = x + 9200

23x = 9200

x = 400 minutes

she would have to talk for at least 400 minutes long distance per month to make it an even or then better deal.

with 400 minutes being the break-even point.

so, to make it a better deal (not just equal), she has to talk for at least 401 minutes per month.