How many electrons are in an electrically neutral atom of boron?

The density of a liquid could be found by using

Aboxcar traveling at 12 m/s approaches a string of 5 identical boxcars sitting stationary on the track. the moving boxcar collides and links with the stationary cars and they all move off together along the track. what is the final speed of the cars immediately after the collision? (you may take the mass of each boxcar to be 18,537 kg.)

Looking at this barometer, is the air pressure high or low? what type of weather would you expect? high, bad low, bad high, good low, good