Answer:

If Mickey has 2.85 meters of ribbon in total and uses only 0.75 to make each pillowcase:

2.85 meters ÷ 0.75 meters/pillowcase = 3.8 pillowcases

Mickey can make approximately 3.8 pillowcases from the 2.85 meters of ribbon she has.

NOW, if Mickey finishes 75 pillowcases...

0.75 meters x 75 pillowcases = 56.25 meters

...Mickey would end up using a total of 56.25 meters to do so