A ball of mass $200\, g$ rests on a vertical post of height $20\, m$ A bullet of mass $10 \,g$, travelling in horizontal direction, hits the centre of the ball After collision both travels independently The ball hits the ground at a distance $30 \,m$ and the bullet at a distance of $120 \,m$ from the foot of the postThe value of initial velocity of the bullet will be (if $g=10\, m / s ^2$ ) :