A stone is dropped from a rising balloon at a height of 300 m above the ground at reaches the ground in 10 s. The velocity of the balloon when dropped was :

Question

$(a)\;19\;ms^{-1}\qquad(b)\;19.6\;ms^{-1}\qquad(c)\;29\;ms^{-1}\qquad(d)\;0\;ms^{-1}$