The following situation can be modeled by a linear function. Write an equation for the linear function and use it to answer the given question. Be sure you clearly identify the independent and dependent variables. Then briefly discuss whether a linear model is reasonable for the situation described. A snowplow has a maximum speed of 55 miles per hour on a dry highway. Its maximum speed decreases by 1.3 miles per hour for every inch of snow on the highway. According to this model, at what snow depth will the plow be unable to move?