Answer:
4
Explanation:
A rectangle has a shorter side and a longer side.
The longer side is called the length and the shorter side is called width.
with the 24 tiles you can make the following rectangles (consider the first number the length and the second number the width, and that each unit represents a tile):
24 x 1
12 x 2
8 x 3
6 x 4
A total of 4 different rectangles.
I am not counting the rectangles than have the same sides shifted, for example 2 x 12 because it is the same as 12 x 2 and we are asked for the rectangles to be different.
I attache an image of the sketch of each rectangle with the labels of length and width (not to scale).