To get this answer, you find the median of the golf pro shop data (a = 40) and the median of the tennis pro shop data (b = 20). Then you subtract to get a-b = 40-20 = 20. The median of any box plot is the vertical line inside the box plot.
the one on the left is 3 times larger than the one on the right. in other words, the right triangle's dimensions times 1/3 is equal to the left triangle's dimensions.
