Question

let a = {2,4,6,8} suppose b is a set with |b| = 5 what are the smallest and largest possible values of |A*B|

Answer 1

The operator you have used is not defined may be possible you are asking | a x b | .

it says every element of a is related to every element of b . so , |axb| simply is |a|*|b|  i.e. 4*5 i.e 20 .