Did you reason that out yourself ames, or is it something you researched? It is pretty well thought out. You are correct that your jump will be 6x higher than on Earth (though how you get to 40-50 feet with this, I don’t know – you must be able to jump really high! Have I seen you in the Olympics?) If you lift your feet 3 feet off of Earth, you can do 18 feet on the Moon. The trick in the riddle was that most people will multiply the height of the bar (5 feet) by 6, which is incorrect because the part of the body that clears that height starts out 3.5 feet above ground to begin with.
I think that the main difference between a jump on the Moon and on Earth is that cracking the faceplate of a spacesuit is not a risk on Earth.