To answer the question, let B call the amount of meat and P the number of potatoes.
The recipe says that for every pound of meat we need 3 potatoes.
Then that relationship is written as follows:
If we increase the amounts of the recipe by 100%, it will multiply by 2 the amount of meat and also that of potatoes. Therefore we need 2 pounds of meat and 6 potatoes.
Then the relationship is:
But
Therefore, the proportion that represents the situation remains the same
This occurs because the increase in the amount of potatoes and beef was in the same proportion.
