c     program to solve a differential equation
c     using Euler's method

      program c4p1
      implicit none

      real x,t,dt,vmax,km

      vmax = 1.0
      km = 0.1
      dt = 0.01
      x = 6

      do 20 t=0,20,dt
         x = x + (-vmax*x/(km+x))*dt
         print *, t,x
 20   continue
      end