Answer:
Yes it is a function.
Domain: (2,20) Range: (1,10)
The following pairing is a function, because no two inputs have the same output. Half of one number is never the same as half of another number.
The domain would be (2,20) because the smallest input is 2, and the largest is 20
and the range would be (1,10) because smallest output would be half of 2 which is 1, and the largest output would be half of 20 which is 10.