Answer:
one possible answer is 9
Step-by-step explanation:
Lets label the total marbles x
then 2:7 can also be written as [tex]\frac{2}{7}[/tex]
But the total parts is 2 +7 is 9, making 2/9 of the marbles blue and 7/9 of the marbles red
So therefore, the total answer has to be a multiple of 9, because we can not have a fraction of a marble.
9 is a multiple of 9 , so it is a possible result
