For the shoe size be equal to the length of the foot, this means that L must be equal to S. Now, since we have different equations depending on your gender, we first check the conditions for man.
Since S = 3L - 22 for men, for a person to have a foot length equal to his shoe size, we equate L to S as shown below.
L = S L = 3L - 22 2L = 22 L = 11
Thus, we can see that men with 11-inch foot would have the same shoe size number. We can apply similar approach to find the length of a woman's foot that satisfies our conditions as shown.
L = S L = 3L - 21 2L = 21 L = 10.5
Hence, a woman with a 10.5-inch foot have 10.5 for a shoe size as well.
