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?

 May 27, 2021

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)

 May 27, 2021

two   ways



Simple method problem 

It has two ways

Mary chooses 1 or 3

Andrew chooses 3 or 1.

 May 27, 2021

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