How many hours in a day would there be if a year was only 50 days

And what else would be of this earth if there were only 50 days in a year?

24 hours still unless the earth was spinning faster or slower. a year is how long it takes the earth to revolve around the sun. a day is how long it take the earth to fully revolve aroung its axis. a day is affected by how fast the earth spins not how fast it is moving in orbit.

it has nothing to do the cycle of a planet traveling around it´s sun with it spinning on it´s axis, so it could be any number of hours or no day at all.

Depends what planet you're on.

The length of a "solar day" (sunrise to sunrise) on Mercury is 176 Earth days, or twice as long as the year, 88 Earth days.

175
.