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Current time:0:00Total duration:2:10

Video transcript

mark pedals his bike seventy times in a minute which of these are reasonable estimates about marks pedaling mark all that apply so let's just think about this a little bit seventy times in a minute so there's 60 seconds in a minute so if he's doing 70 times in a minute fuze doing 60 times in a minute then he would be doing he would be pedaling once per second since he's doing 70 times in a minute he's doing a little bit more than once per second so let's maybe that'll help us right over here so here it says mark pedals his bike what 4,000 times everything well that's nuts if he pedaled his bike 4,000 times every second you'd have a way huger number right over here you'd have 4,000 times per second times 60 seconds per minute you would have a huge number right over here if it's 70 times in a minute we just we just reasoned that he pedals a little over one time in a second so this is definitely this is definitely not right mark pedals his bike about once every hour well an hour's 60 minutes so if he does 70 times in a minute he's going to do 60 times 70 in an hour so this is also crazy that he only does once in an hour this is unbelievably slow mark pedals his bike about once every second well we've already reasoned that there's 60 seconds in a minute and he does 70 times in a minute so he does a little over what if you divide 70 by 60 so you could divide 70 by 60 and you're going to get a number that's this is going to be one well I don't want to go into you're going to get a number that's a little bit over one time per second so this is right we're estimating we don't have to get exact numbers it's about once every second so that seems legitimate mark pedals his bike about 4,000 times every hour so let's think about that if you pedals 70 times in a minute and then there are 60 minutes in an hour this is going to be equal to 70 times 60 well we can multiply the 7 times the 6 and we get 7 times 6 is 42 and we have 2 zeros here so we have exactly 42 hundred times every hour so as an estimate this is pretty close so I would go with that as well