Minxia counted 40 green cars and 20 silver cars in the parking lot. If the number of green cars stays the same, how many more silver cars would need to be added so the ratio of green cars to silver cars is 1 to 3?

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.