Answer:
Number who walk to school = 16
Explanation:
If there are 42 students, and 23 girls, there must be 19 boys since 19 + 23 = 42.
If ten girls walk to school, then there are 13 girls left to sort.
Since 7 of the 11 students on the bus are boys, that means 4 girls ride the bus too, so we have 9 girls left.
All we have left is cycling, so 9 girls must cycle to school.
Now, all we have to do is add 6 and 7 since 6 boys bike and 7 boys ride the bus. That equals 13 boys who do not walk.
19 boys total - 13 boys who dont walk = 6 boys that walk.
6 + 10 = 16
Number who walk to school = 16