Carlos has 30 yards of plastic fencing to set up for a track meet he uses 85 feet of fencing how much fencing does he have left

There's 90 feet in 30 yards so 90 - 85 is 5

The first thing you need to know is that 1 yard = 3 feet. Therefore if he had 30 yards he had 90 feet of plastic fencing. From there all you have to do is take the 90 feet he has and subtract 85 feet he uses. That means Carlos has 5 feet of fencing left.