Learn about Percents and Their Applications In this lesson, let’s learn how to apply percents to real life problems. So the graph below shows us the various types of movies rented over a period of time. So the circle graph shows us drama was 96, 320 action movies, 200 comedies, 160 musicals and 24 other. So what are percents? Percent is nothing but a ratio where it is a value x/100, one of the denominators and the ratio is always 100. So the two things to remember, this is how you express the percent, x% = x/100. So 35% is 35/100 as a ration. Second, anything that is part over a whole can be expressed as a percent over a hundred. So this is what we’re going to use to do some of these problems. What percentage of the movies rented were comedies? Well, we know that the number of movies that were comedies were 200. That is the part. How many make up the whole? How many total movies? So total number of movies rented were 800 by this graph. So 200/800 is whatever percent we’re trying to find over a hundred. So if this is the proportion 800 x P = 20,000 or P = 25. So percent of the movies that were comedies is 25%. Let’s try the second one. What type of movie made up 20% of the rentals? So first what is 20% of rental? We need to find 20% of the rentals so 20/100 is this part, what is that? That is y/800 because the total number of movies is 800 which means 100 x y = 16,000 or y = 160. So 20% of all the movies is 160. What made 160? Well musical was 160 so what type of movie made 20% of the rentals? That is musicals. The key thing to remember is this part, part over a whole so if you take anything that’s in its entirety and we want to have a ratio between a part and a whole part equals P/100 that has been expressed in percent will be percentage value over a hundred. Percentage is any ratio that has a denominator of 100. So if this is true then if you want to find out what percentage of the movies were comedies. That’s the value we’re looking for. This over a hundred would be the part that was comedies. That’s 200 over the total which is 800 We solve and we got P = 25 which means this can be written as 25%. Similarly if you want to find 20% of the rentals, well 20% equals 20/100 would be equal to whatever value that meant over 800 because what is 20% of 800 is what we’re trying to figure out. Well that answers 160 because the cross products are true then we define what movies were rented out 160 times? Well, that was musicals.