Answer:
20 and 40
Explanation:
3x7 is 21 but thats only one too much it has to be 3 too much to go down one and be a factor
6x4 is 24 it has to be 6 too much to go down one to be a factor
20x1 and 40x1/2 are both factors unless your teacher doesn't include fractions, so just choose this for now and if you get it wrong ask your teacher because three and six arent