A mass of \( 50\,\text{kg} \) is placed at the centre of a uniform spherical shell of mass \( 100\,\text{kg} \) and radius \( 50\,\text{m} \). If the gravitational potential at a point, \( 25\,\text{m} \) from the centre is \( V \) kg/m. The value of \( V \) is:
