Let the total time be = to + t
we have to find t
So for 1st particles S= 1/2 g (to + t)2
and for second particle S= ut + 1/2gt2
for both displacement is same
1/2 g (to + t)2=ut + 1/2gt2
solve for t you will get the answer
- Himanshu Giria I too did like this but the answer is wrong