# On chatty cathy’s cell phone plan she pays for minutes used plus a fixed monthly charge.

On chatty cathy’s cell phone plan she pays for minutes used plus a fixed monthly charge. for 500 minutes she pays $35 total, and for 1500 minutes used she pays$55 total. what is her monthly fixed charge?

## This Post Has 7 Comments

1. Expert says:

the correct choice is marked

step-by-step explanation:

the first two graphs show multiple turning points. the last graphs matches the description in every detail.

2. winterblackburn78 says:

C) $25 Step-by-step explanation:$25 is correct. The slope of the line from (35, 500) to 55, 1500) is 20/1000 = .02, which is her cost per minute. Plug in one of the points into the equation y = mx + b to find b, which is the fixed cost.

Hope this helps

-Amelia

3. kbuhvu says:

Find out  the what is her monthly fixed charge .

To prove

Let us assume that the cost per mintues = x

Let us assume that the monthly charge be = y

As given

n Chatty Cathy’s cell phone plan she pays for minutes used plus a fixed monthly charge.

For 500 minutes she pays $35 total Than the equation becomes 500x + y = 35 As given for 1500 minutes used she pays$55 total.

Than the equation becomes

1500x + y = 55

Subtracted 500x + y = 35 from 1500x + y = 55

1500x - 500x + y - y = 55 - 35

1000x = 20

$x = \frac{20}{1000}$

x = $0.02 Put in the 500x + y = 35 500 × 0.02 + y = 35 10 + y = 35 y = 35 - 10 y =$25

Therefore the monthly fixed charge be $25. 4. Expert says: problem: f(x) = - 2/3x + 5; f(5/2) substitute 5/2 in for x: f(5/2) = -2/3(5/2) + 5 simplify the right side: f(5/2) = -5/3 + 5 f(5/2) = 10/3 f(5/2) = 10/3 i hope this ! 5. ashleyheink3796 says: We are given : For 500 minutes she pays$35 total and for 1500 minutes used she pays $55 total. So, we can put the given information in form of two coordinates : ( Number of minutes, Total amount). (500, 35) and (1500, 55). First we need to find the slope between those two coordinates. $\mathrm{Slope\:between\:two\:points}:\quad \mathrm{Slope}=\frac{y_2-y_1}{x_2-x_1}$ $\left(x_1,\:y_1\right)=\left(500,\:35\right),\:\left(x_2,\:y_2\right)=\left(1500,\:55\right)$ $m=\frac{55-35}{1500-500}$ $m=\frac{1}{50}$ Now applying slope-intercept form y=mx+b, where m is the slope and b is y-intercept. y-intercept represents monthly fixed charge. Plugging (x,y) = (500, 35) and slope m= 1/50 in slope-intercept form y=mx+b. 35 = 1/50 (500) +b 35 = 10 + b. Subtracting 10 from both sides, we get 35-10 = 10-10 + b b = 25. Therefore, her monthly fixed charge is$25.

6. chrismax8673 says:

$25 Step-by-step explanation: 500 mins =$35 (fixed + per minute charge)

1500 mins = $55 (fixed + per minute charge) If we let per minute charge be "m" and let fixed charge be "f" we can write 2 equations as: 35 = 500m + f and 55 = 1500m + f Now, We re-write both equations in terms of f and equate both expressions: f = 35 - 500m and f = 55 - 1500m Equating: 35 - 500m = 55 - 1500m -500m + 1500m = 55 - 35 1000m = 20 m = 20/1000 m = 0.02 Now we find f, what we are looking for: f = 35 - 500m f = 35 - 500(0.02) f = 25 So, the fixed charge is$25

7. krystalsozaa says:

Option 'C' is correct.

Step-by-step explanation:

Let the fixed monthly charges be x

Let the charges per minutes be y

According to question, we have

$x+500y=\35\\x+1500y=\55$

Now, by using the method of substitution  for solving the system of linear equation:

$x=35-500y\\\\\text{ put in second equation i.e.}x+1500y=\55\\\\35-500y+1500y=55\\\\35+1000y=55\\\\1000y=55-35\\\\1000y=20\\\\x=\frac{20}{1000}\\\\x=\frac{1}{50}$

Now, put the value of y in x , so we get,

$x=35-500y\\\\x=35-500\times\frac{1}{50}\\\\x=35-10=\25$

Hence, the monthly fixed charge is \$25

Thus, Option 'C' is correct.