Arecipe calls for 2 cups of flour to make 2 dozen cookies. use the proportion to calculate how much flour is needed to make 6 dozen cookies. 2 cups/2 dozen= x cups/6 dozen
a.

If 2 dozens = 2cups
   6 dozens =x
2cups/2 dozens=x cups/6 dozens
2c/2d=6d/x
multiply the first number on the left side of the equation to the last on the other side of the equation and the rest
2*x=2*6
2x=12
2x/2=12/2
x=6
Therefore  6 cups will be needed to make 6 dozens of cookies