Andrew chooses a number from 1 to 100, and Mary also chooses a number from 1 to 100. (They may choose the same number.) It turns out that the product of their numbers is a mutliple of 3. In how many ways could Andrew and Mary have chosen their numbers?
I think to be a multiple of three one of the two numbers must also be multiple of 3
33 numbers are mutilples of 3 between 1 -100
the other number can be any of the 100
33 x 100= 3300 ways if at least ONE of the two chose a 3 multiple
(so there are 3300 pairs of numbers that will produse a number that is a multiple of 3......if the ORDER of the numbers does not matter....i.e. it does not matter who chose which of the pair.....which is what I expect your questioner wants for an answer)