Answer :


2 1/2 * 5 = 12 1/2 cups of flour are needed to make 5 batches

5/2 * 5/1=25/2 or 12 1/2 cups

the simplest way is to convert 2 1/2 to decimal 2,5 then multiply by 5 2.5 x 5=12.5 or 12 1/2 cups of flour