Question about Velocity, time, height!

1. The problem statement, all variables and given/known data

Q: An object thrown upwards at V0 reaches a maximum height of 100 m.
a. Calculate the initial velocity of V0.
b. Calculate the total flight time.
c. Calculate the height of the object when v=30 m/s.

2. Relevant equations

That is my question what equations do i need to solve this.

3. The attempt at a solution

Sorry i couldn't attempt because i couldn't find the appropriate equation.

 

Thanks!