Vertical Projectile Motion

The block is thrown from the ground with a certain upwards velocity. it reaches the maximum height of 19.6m in 2 seconds. What is the initiated velocity on the ground when the block was thrown?

Considering the symmetric movement of the projectile from the ground and retaining to the same ground. The object initial velocity is 20m/s upwards and reach a maximum height at a certain magnitude. What is the maximum height?

Considering the symmetric movement of the projectile from the ground and retaining to the same ground. The object initial velocity is 20m/s. What are it final velocity.