\magnification=\magstep1

$$
M_{r,101} \quad = \quad M_{r,100} \ + \ {{dM_{r}}\over{dr}} \biggr|_{100}
$$

$$
Q_M \quad \equiv \quad 1 \ - \ {{M_r}\over{M_{\rm tot}}}
   \qquad \qquad \Rightarrow \qquad
     M_r \quad = \quad M_{\rm tot} (1 \ - \ Q_M)
$$


$$
{\rm lifetime \ T} \quad \sim \quad 
{{\rm amount\ of\ fuel}\over{{\rm rate\ of\ burning\ fuel}}}
    \quad = \quad 
       {{M}\over{L}}
$$


\bye
