To solve this problem it is necessary to apply the concepts related to the kinematic equations of motion for which the height of a particle is defined as a function of gravity as,
Where,
h = Height
g = Gravity constant
v = Velocity
There is not change in the horizontal component, therefore there is only the component horizontal given (18m/s) and the vertical component:
Applying the vector theory to find the magnitude of a vector we have to
The speed at which the ball was thrown was 25.38