(c) Let $x$ be the distance of point from the smaller body where gravitational intensity is zero.
$\therefore\ \frac{Gm_{1}}{(1 - x)^{2}} = \frac{Gm_{2}}{x^{2}}$
or $\frac{x}{1 - x} = \sqrt{\frac{m_{2}}{m_{1}}} = \sqrt{\frac{1000}{100,000}} = \frac{1}{10}$
or $10x = - x$
or $x = (1/11)m$