As energy is just a transfer, energy is neither created nor destroyed.
Assuming that there is no air friction, Kinetic energy is equal to gravitational potential energy
KE = GPE (short form)
½mv2 = mgh
where m=mass (kg), v= velocity (m/s), h=height (m)
Gravitational potential energy is the amount of energy an object at a height has the potential to do, or the amount of work it has potential to do due to gravitational force.
In question form, we know that g is equal to gravity, 10m/s
Also, if we do not know the mass of the item, we can omit it in the equation because they cancle each other out.
½v2 = gh
You only need one piece of information because you already know that g = 10m/s