A car is moving along a straight road with uniform acceleration. It passes through two points $P$ and $Q$ separated by a distance with velocity $30 \mathrm{km} {\mathrm{h}}^{-1}$and $40 \mathrm{km} {\mathrm{h}}^{-1}$ respectively. The velocity of the car midway between $P$ and $Q$ is

• A

  $33.3 \mathrm{km} {\mathrm{h}}^{-1}$
• B

  $20\sqrt{2} \mathrm{km} {\mathrm{h}}^{-1}$
• Correct answer
  C

  $25\sqrt{2} \mathrm{km} {\mathrm{h}}^{-1}$
• D

  $35 \mathrm{km} {\mathrm{h}}^{-1}$

Hence, the correct answer is option: 'C'.