How to calculate how much acetic acid should be theoretically yielded from a process that is 75% efficient and actually yields 500.0 ml (assume the density of acetic acid = 1.05 g/ml)

Mike and mitchell decide to have a foot race. they mark off a stretch of 100 yards, and recruit cindy to work the stopwatch. after running the race and looking at the results, cindy declared that mitchell was the fastest. so how did the boys times compare?