For the shoe sizes in Exercise 16, what might be the problem with either the mean or the median as a measure of center?

Data From Exercise 16

A last is a form, traditionally made of wood, in the shape of the human foot. Lasts of various sizes are used by shoemakers to make shoes. In the United States, shoe sizes are defined differently for men and women:
U.S. men’s shoe size = (last size in inches x 3) – 24
U.S. women’s shoe size = (last size in inches x 3) – 22.5
But in Europe, they are both: Euro size = last size in cm x 3/2
Here is a histogram of the European shoe sizes of 269 college students (converted from their reported U.S. shoe sizes):

a) Describe the shape.
b) How many modes do you see? What might explain that?

Count 60 50 40 30 20 10 34 36 38 40 42 44 46 48 50 Shoe Size