The best thing to do here is simply to list all of the actors for each number and this will let you see the GCF,
28- 1,2,4,7,14,28
42- 1,2,3,6,7,14, 21, 42
Therefore, you're correct and 14 is the GCF
Hope this helps :)
I would argue that it does due to that if it increased, it's either from a 30% chance that nothing changed or that the teachers did it. Since 100-30=70, there's a 70 percent chance that the teaching effect did work!
