Answer:
11 boys walk to school each day
Explanation:
*The following will be assumed: the only genders of students in the class are male or female; the only options for getting to school are walking or not walking
If there are 32 students in the class total, and there are 15 boys,
32 - 15 = 17
there are 17 girls.
If 8 of these girls do not walk to school,
17 - 8 = 9
9 girls walk to school
So, if 20 total students walk to school, and 9 of those are girls
20 - 9 = 11
11 boys walk to school each day.