To what height should a body weighing 15 kg be lifted to increase its potential energy by 45 J?

We take the initial position of the body as the zero reference level.
Potential energy (in the gravitational field of the Earth) Ep (45 J) = mgh, where m is the mass of the body (15 kg), g is the acceleration of gravity (10 m / s ^ 2), h is the height of the body above the zero level,
It follows from this that h = Ep / mg;
h = 45 / (15 * 10) = 0.3 m.
Check: m = J / (kg * m / s ^ 2) = (kg * m ^ 2 / s ^ 2) / (kg * m / s ^ 2) = m.
Answer: the body must be raised to a height of 0.3 m.