Need help badly

[Unknown008]

0.1x=10 I am not sure what I should do with this next im sorry.

Hmm, let's try another way.

What number, when multiplied by 0.1 gives 10?

 

[swerve78]

10 right or am I really confused.

 

[Unknown008]

I think you're a little tired

0.1 is $\displaystyle \frac{1}{10}$

And this multiplied by 10 gives:

$\displaystyle \frac{1}{10}\times 10 = 1$

Not 10!

 

[swerve78]

so one is my answer to how many minutes a month I need?

 

[Unknown008]

Nuh huh. 100 should be your answer.

100 divided by 10 gives 10.

See how it works:

$\displaystyle 0.1(100) = 10$

And from our two initial equations:

$\displaystyle y_A = 0.22x + 25 = 0.22(100) + 25 = 47$

$\displaystyle y_B = 0.12x + 35 = 0.12(100) + 35 = 47$

So anything longer than or equal to 100 minutes is your answer.

Here is the graph of the two lines:

The blue line represents the total cost that company A charges and the purple line represents the total cost that company B charges. You see that for the most part, the line for company B is above that of company A, meaning that for those minutes, company B is more expensive. The point where they meet is where they charge the same fee and as soon as the purple line goes blow the blue line, company B is charging less expensive fees.