Peter can mow the lawn in 40 minutes and John can mow the lawn in 60 minutes. How long will it take for them to mow the lawn together?

If they mow the lawn together you would subtract 40 from 60 and your answer would be 20.
60 - 40 = 20

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.