The graph to the right shows some of the winning times (in minutes) of an annual race from 1953 to 2002, together with a linear approximation of the data.

(a) The equation for the linear approximation of this data is y=−0.02320x+55.31. What does the slope of this line represent? Why is the slope negative?

(b) Use the approximation to estimate the winning time in 2016.

The winning time will be approximately   _____ minutes.

(Round to the nearest whole number as needed.)