In your marble collection, 4/7 of the marbles are blue and 4/21 of the marbles are red. How many times more blue marbles do you have than red marbles?

Answer 1

(4/21)*x= (4/7) so multiply the reciprocal of (4/21) to both sides to leave x by itself

x=(4/7)*(21/4) the 4's cancel each other since one is at the top and the other is at the bottom

x=21/7

x=3

Check (4/21)*3= (4/7)

So 3 times of the blue marbles you have than the red marbles.