Hey mathmagix.

For this problem you should consider what possibilities can generate the following relations.

What is the value of the floor function in terms of its inputs to return 3 in the 2nd answer?

Based on this can you get an in-equality for xy? (Hint: if z = [n,n+1) for integer n then floor(z) = n. So the range for [n,n+1) is the range you need to consider for the input.