Arecipe for beef stew calls for 1 pound of beef and 3 potatoes. the recipe is doubled to include 2 pounds of beef and 6 potatoes. which proportion represents the situation?

The proportion that represents the situation is:

1 pound of beef           2 pounds of beef
=    
   3 potatoes                        6 potates

As you see, when you double thre recipe you multiply both numerator and denominator by 2: 1 pound of beef * 2 = 2 pounds of beef, 3 potatoes * 2 = 6 potatoes.

Of course, the fraction 1/3 is equivalent to the fraction 2/6.