So the given statement is p→q
Now for a contrapositive statement, by definition we have (p→q)↔(¬q→¬p)
So ¬q means "i do not go to school" and ¬p means "it rains"
¬q→¬p means "if i do not go to school, it rains"
If I do not go to school, it rains.
If it rains, I go to school.
If i go to school, it rains.
If it rains, I do not go to school.
In the given statement, let p denote the part "it does not rain" and q denote the part "i go to school"
So the given statement is p→q
Now for a contrapositive statement, by definition we have (p→q)↔(¬q→¬p)
So ¬q means "i do not go to school" and ¬p means "it rains"
¬q→¬p means "if i do not go to school, it rains"