There's 4 as in the denominator which cancels out the 2 in the numerator. Thus leaving you with 2 as in the denominator. Then there's only 1 b I the denominator which is canceled out by the ones in the numerator, leaving you with only 4 b's in the numerator. Finally there is only 1 c in the numerator which is canceled out by the ones in the denominator. Thus leaving you with 2 c's in the denominator.
For this all you have to do is take the numerator and multiply it by 3 4*3=12 3 bottles contain 2.4 liters of root beer. or 3 bottles contain 12/5 liters of root beet