Asalesman earns 3000 per week plus a 5% commission on all sales over 8,000 one week his sales amounted to 15,000 what were his earnings that week

Total earnings were $3000 + 0.05(15000-8000)
                               =$3000 + 350 = $3350

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.