Explanation

$n_{2} = n_{1}\left\lbrack \frac{L_{1}}{L_{2}} \right\rbrack^{1}\left\lbrack \frac{T_{1}}{T_{2}} \right\rbrack^{- 2} = 10\left\lbrack \frac{m}{km} \right\rbrack^{2}\left\lbrack \frac{\sec}{hr} \right\rbrack^{- 2}$ $n_{2} = 10\left\lbrack \frac{m}{10^{3}m} \right\rbrack^{1}\left\lbrack \frac{\sec}{3600\ sec} \right\rbrack^{- 2}$=129600