Given, time taken by the stone to cover distance d1,t1=4s Time taken by the stone to cover distance d2, t2=8s ∵ Stone is falling freely, hence its initial speed u is zero and acceleration due to gravity, g=10m∕s2. As we know that, h‌‌=ut+(‌
1
2
)gt2 ∴‌‌d1‌‌=0+(‌
1
2
)×10×42 ‌‌=80m Let distance travelled by stone in total time t=4s+8s=12s be d Again from Eq. (i), we get d‌‌=‌