Puzzle 1: a + b = 10
b - a = 8
b x a = ?

Puzzle 2:

a + b + b = 24
b - a = 6
a x b = ?

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.