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Current time:0:00Total duration:2:04

Part:whole ratio word problem

CCSS.Math: ,

Video transcript

in a language class the girl - boy ratio is 5 to 8 so for every 5 girls we have 8 boys if there are a total of 65 students how many girls are there so this is interesting they give us the ratio of girls to boys but then they want us to think about how many girls there are given that there are 65 total students so what we really want to think about is not just the ratio of girls to boys we want to think about the ratio of girls to total students total students so how can we figure out what this ratio is going to be well the girl the boy ratio gives us a good clue the ratio for if there's five girls for every eight boys how many how many total students are there going to be for every five girls well for every five girls you're going to have five girls and eight boys you're going to have 13 total students so I just added the 5 and the 8 right over here the ratio of girls to total students is 5 to 13 one way of thinking about it is if you were to evenly divide the students into groups of 13 every group of 13 students would have 5 girls now I think we're ready to figure out how many total girls there are because they tell us that there are 65 students there are 65 students so we don't just have one group of 13 we have 65 students and how many groups of 13 is 65 well to go from 13 to 65 you have to multiply you have to multiply by 5 5 times 10 is 50 5 times 3 is 15 right 13 times 5 is 65 so you essentially you could one way you could do it is you have five groups of 13 so if you have five groups of 13 each of those are going to have five girls multiplied by five you're going to have you're going to have 25 girls so for every 65 students you're going to have 25 girls given the information that has been given