a hard maths puzzle

I'm having trouble posting this so i'm sorry sorry if it posted twice.

Here's a maths puzzle for anyone who wants to try it, the answer to my last one was 175, well done markr

this puzzle is from neopets by the way

____________________
The writer of the Lenny Conundrums decided, as a New Year's resolution, to make the Lenny Conundrums a little more challenging, because it seemed like everyone was complaining abut how easy the puzzles were.

His second New Year's resolution was to learn a new hobby. The hobby he chose was structural engineering. So he enrolled in the Brightvale Institute of Technology and Engineering. While studying there, he observed a new building being constructed.

There was a steel beam 50 feet long. The entire Skeith construction crew (total weight: 6000 pounds) was standing at the center of the beam. Assume the modulus of elasticity is 29,000,000 pounds per square inch, the moment of inertia is 850 inches^4, the beam has simple pin connections at either end, and all loads other than the weight of the crew are disregarded.

How much will the beam deflect? Please round to the nearest tenth of an inch.

_______________________-