2couches against the wall
1 takes up 4/9 of the wall and the other takes up 1/5 of the wall how much of the wall is covered by couches

4/9 + 1/5 (common denominator is 45)
20/45 + 9/45 = 29/45

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.