Q:

The monthly cost (in dollars) of a long-distance phone plan is a linear function of the total calling time (in minutes). The monthly cost for 50 minutes of calls is $12.55 and the monthly cost for 102 minutes is $17.23. What is the monthly cost for 101 minutes of calls?

Accepted Solution

A:
The monthly cost will be $17.14Step-by-step explanation:Given that the monthly cost (in dollars) of a long-distance phone plan is a linear function of the total calling time (in minutes) then this can be presented in a table form as;Time in minutes (x)        Cost in dollars (y)50                                          $12.55102                                         $ 17.23Take the values as ordered pairs to represent coordinates for points that satisfy the linear function(50,12.55)  and (102,17.23)Finding the slope of the graph using these pointsslope,m=Δy/Δxm=Δy=17.23-12.55 =4.68Δx=102-50=52m=4.68/52 =0.09Finding the equation of the linear function using m=0.09, and point (50,12.55)m=Δy/Δx0.09=y-12.55/x-500.09(x-50)=y-12.550.09x-4.5=y-12.550.09x-4.5+12.55=yy=0.09x+8.05So for 101 minutes , the cost will be;y=0.09*101 +8.05y=9.09+8.05 = $17.14Learn MoreLinear functions : : linear function#LearnwithBrainly