A parking garage charges $5.50 to park for 4 hours and $7.75 to park for 7 hours. If the cost is a linear function of a number of hours parked, what is the cost to park for 3 hours?
The cost per hour of parking is the gradient of the line and can be determined by: (7.75 - 5.50) / (7 - 4) = $0.75 per hour parking 5.50 = 0.75 x 4 + c c = $2.50 The equation is: y = 0.75x + 2.5 The cost for three hours (x = 3) is: y = 0.75(3) + 2.5 y = $4.75
