It takes 20 minutes for 5 people to paint 5 walls.
How many minutes does it take 9 people to paint 9 walls?

The major difference is that a histogram is only used to plot the frequency of score occurrences in a continuous data set that has been divided into classes, called bins.  bar charts, on the other hand, can be used for a great deal of other types ofvariables  including  ordinal  andnominal  data sets.