Can someone help me with this problem?

a) 2

b) 3

c) 1

hope this helps :)

4 and 5)16.97 or 12√2

6)15.59 or 9√3

7)y = 15.59 or 9√3     x =27

8)17.80

lockers 1, 4, 9, 16, 25, 40, and 49 are open

i ran through it by the other answer is wrong