from top of a tower a stone is thrown up and it

Question

From top of a tower a stone is thrown up and it reaches the ground in time t1. A second stone is thrown down with the same speed and it reaches the ground in t2. A third stone is released from rest and it reaches the ground in time t3 then t3= ?

solution)

let the intial speed be ''u'' and height be ''h''.

h(-j)=u(j)*t1+0.5g(-j)*t1²

Case(2)

h(-j)=u(-j)*t2+0.5g(-j)*t2²

Case(3)

h(-j)=0.5g(-j)*t3²

 

solve case 1 and case 2 for t1 and t2 (quadratic) .