1.
Two bodies of mass 1kg1\,\text{kg} and 3kg3\,\text{kg} have position vectors i^+2j^+k^\hat{i} + 2\hat{j} + \hat{k} and 3i^2j^+k^-3\hat{i} - 2\hat{j} + \hat{k}, respectively. The centre of mass of this system has a position vector