Lisa has five times as many books as she has cds. she must be either over 45 or a librarian. lisa also has 35 books. okay, scratch that. she just hates music. how many cds does she have?

Simple, she has X= 7 CDs

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.