Like this:
1). Ignore the 22.7 m/s horizontal speed. It doesn't make a bit of difference, and the answer doesn't depend on it. (A bullet fired horizontally from a rifle and another bullet dropped from the end of the rifle barrel at the same time both hit the ground at the same time.)
2). Calculate how long it takes an object dropped from rest to fall 42.3 m. Use the "dropped from rest" formula:
Distance = (1/2) (acceleration) (time)²
3). In the formula, "acceleration" is the acceleration of gravity. If this story happened on Earth, then use the acceleration of gravity on Earth. That's 9.81 m/s² .
I wish I could make it more complicated for you, but I don't know how.
