how many prisms can u make with volume of 40

Answer 1

assuming you mean rectangular prisms with edges of integer length, just start listing unique triples of factors of 40.
1 1 40
1 2 20
1 4 10
... on to ...
2 4 5
Then count the list.

Answer 2

and
40 = 8*5 = 1*2*2*2*5
so play with
1
2
5
4
8
10
20