Question

A cell phone service provider charges customers a fixed rental charge and a call charge based on the number of call minutes. The customers enjoy free text messaging and Internet usage. The table shows the monthly bill amount for different call minutes. Call Minutes 125, 150, 175, 200 and the Bill Amount ($) 125 75 150 85 175 95 200 105 Based on the data, match the bill amounts with their corresponding call minutes. Tiles $74.80 $76.20 $77.80 $78.60 $79.20 $80.40 $82.60 $84.20 Call Minutes are 128,132,134,144 match tiles with these

Answer 1

We are given the following data in tabulated form:

 

Call minutes, y                                   Bill Amount ($), x

125                                                         75          

150                                                         85

175                                                         95

200                                                         105

 

We can see that for every 25 increase in call minutes, there is a constant 10 increase in bill amount. Therefore the equation relating the two variables is linear. The call minutes is y while the bill amount is x, therefore:

y = m x + b

where m is the slope and b is the y-intercept

 

Calculating for the slope m:

m = (y2 – y1) / (x2 – x1)

m = (150 -125) / (85 – 75)

m = 2.5

 

So, y = 2.5 x + b

 

Calculating for b using the 1st pair:

125 = 2.5 (75) + b

b = - 62.5

 

So the final equation is:

y = 2.5 x – 62.5

 

To match, simply plug in the value of the bill amount ($) as x in the equation and the answer will be y which is the call minutes.

Answer 2

in case u didn’t wanna do the math:

128 = $76.20

132= $77.80

134= $78.60

144= $82.60