Answer:
12
Explanation:
they should use 12 tables to make a rectangle
12 has more factors than 13 which only has 2
12 has 1 2 3 4 6 & 12
13 only has 1 & 13
when using 12 desks you would have 6 ways of rearranging the table
1x12; 2x6; 3x4; 4x3; 6x2; 12x1
this has the most amount of ways while with 13 you only have 2 ways
1x13 and 13x1