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?
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.
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.
To find the amount of calling for which the two plans cost the same, we need to set up an equation where the total cost of Plan A equals the total cost of Plan B. Let's use x to represent the number of minutes of calls.
For Plan A, the total cost is given by:
$11 + $0.18x
For Plan B, the total cost is given by:
$18 + $0.13x
Setting the two equations equal to each other:
$11 + $0.18x = $18 + $0.13x
Now, we can solve for x to find the amount of calling for which the two plans cost the same.
$0.18x - $0.13x = $18 - $11
$0.05x = $7
x = $7 / $0.05
x = 140
Therefore, the amount of calling for which the two plans cost the same is 140 minutes.
To find the cost when the two plans cost the same, we substitute the value of x into either equation.
Using Plan A to calculate the cost:
Total cost for Plan A = $11 + $0.18 * 140
Total cost for Plan A = $11 + $25.20
Total cost for Plan A = $36.20
Therefore, when the two plans cost the same for 140 minutes of calling, the cost is $36.20.