The equivalent conductance  at infinite dilution for $KCl$  and  $KN{O}_3$  are 60 and 50  $s{m}^{-1}e{q}^{-1}$. If the equivalent conductance of  $C{l}^{-}$  at infinite dilution is 40, then the conductance of  $N{O}_3^{-}$  is $x\times 10$  find  $x$ .