Problema Solution
Given that the cost of 20 hours of Internet service is $40 and the cost for 50 hours is $55. Assume that there is a linear relationship between cost and the number of hours of service. Find the linear function, f(x), that describes the cost of use for x hours of service. Then use your function to determine the cost of 80 hours of Internet service.
Answer provided by our tutors
(20,40), (50,55) are two points.
slope m =(55-40)/(50-20).
=15/30=1/2.
The equation is y-y1=m(x-x1).
y-40=1/2(x-20).
y-40=0.5x-10.
y=0.5x-10+40.
y=0.5x+30.
Cost of 80 Hrs of service =0.5*80+30.
=40+30.
=$70.