Can Someone help me with this. I will upvote$($a$)$

Calculate the height $($in m$)$ of a cliff if it takes $2\mathrm{.}13$ s for a rock to hit the ground when it is thrown straight up from the cliff with an initial velocity of $8\mathrm{.}19$ m$/$s$.$

$($b$)$

How long $($in s$)$ would it take to reach the ground if it is thrown straight down with the same speed?