300 out of 500 people went on a trip what percentage of people were not able to go on the

6 percent because 300/500 equals 0.6.

Well, there are 500 people, but only 300 are coming on the trip. That means that 200 people aren't going on the trip. Therefor, 200/500 is the fraction you would use. Now, just simplify the fraction. 200/100=2, and 500/100=5, so the fraction simplifies down to 2/5. 2/5 equals 40% so 40% of the people were not able to go on the trip.