Give the starting value a, the growth/decay rate r, and the continuous growth/decay rate k. If there is exponential is decay, then your growth rates should be entered as negative percents.
 
$\displaystyle Q = \frac{140}{ e^{0.181(t - 1)} }$ has:
 
          $a =$ (round to 4 decimal places)
          $r =$ % (round to the nearest 0.01%)
          $k =$ % (round to the nearest 0.01%)