Joseph plots the speed of his car and time on a scatter plot. The equation for the line of best fit on his scatter plot is y = -15x + 60, where x is the time in hours and y is the speed in miles/hour. Which statement describes the situation correctly?
The initial speed is 60 miles/hour, and his speed decreases by 15 miles/hour every hour.
The initial speed is 60 miles/hour, and his speed increases by 15 miles/hour every hour.
The initial speed is 0 miles/hour, and his speed increases by 15 miles/hour every hour.
The initial speed is 5 miles/hour, and his speed increases by 30 miles/hour every hour.