Tanisha is planning that each person attending the party will eat one hamburger. Tanisha uses 1/4 pound of ground beef to make each hamburger patty. How many pounds of ground beef will Tanisha need to buy so that each guest has a hamburger?

Here we do not know the number of persons that will attend the party, but suppose that it is the number A, where A is a whole number.

For each of the A persons invited to the party, Tanisha needs to use 1/4 pound of ground beef to make a hamburger.

Then we need A times 1/4 pounds of ground beef.

The total ground beef needed is: A * (1/4) pounds = A/4 pounds.