A body of mass 2 kg is moving towards north with a velocity of $20 \mathrm{~m} \mathrm{~s}^{-1}$ and another body of mass 3 kg is moving towards east with a velocity of $10 \mathrm{~m} \mathrm{~s}^{-1}$. The magnitude of the velocity of the centre of mass of the system of the two bodies is

• A

  $20 \mathrm{~m} \mathrm{~s}^{-1}$
• Correct answer
  B

  $10 \mathrm{~m} \mathrm{~s}^{-1}$
• C

  $15 \mathrm{~m} \mathrm{~s}^{-1}$
• D

  $2 \sqrt{5} \mathrm{~m} \mathrm{~s}^{-1}$

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