Q:  What is the value of the Hubble constant
      based on Hubble's distance estimates?


         From the diagram, we see the slope is 
         roughly

                       rise
           slope  =  ---------
                       run

                      (1000 km/s  -  0 km/s) 
                  =  ------------------------
                       (2 Mpc     -  0 Mpc)


                        500 km/s
                  =   -------------
                           Mpc