A phone company offers two monthly plans. Plan A costs
$11
plus an additional
$0.18
for each minute of calls. Plan B costs
$18
plus an additional
$0.13
for each minute of calls. For what amount of calling for the two plans cost the same? What is the cost when the two plans cost the same?
3 answers
I know in order to find the amount of the calling plans you have to set up a table and multiply until you get the same number but I posted this question because I have no absolute way to do it.
11 + .18m = 18 + .13m
Solve for m, then substitute value for m on either side.
Solve for m, then substitute value for m on either side.
costA = 11 + .18m
costB = 18 + .13m
they are the same when
11+.18m = 18 + .13m
.18m - .13m = 18 - 11
.05m = 7
m = 7/.05 = 140
at 140 minutes they are the same
costA = 11 + .18(140) = $36.20
You do costB and show that my answer is correct.
costB = 18 + .13m
they are the same when
11+.18m = 18 + .13m
.18m - .13m = 18 - 11
.05m = 7
m = 7/.05 = 140
at 140 minutes they are the same
costA = 11 + .18(140) = $36.20
You do costB and show that my answer is correct.
3 answers