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 one year ago
you, in your new red Porsche, decide to make a 160km trip to Carolina Beach, traveling at 80km?hr. Your make a return trip at a rate of 48km?hr. What was your average speed for the entire trip?
 one year ago
you, in your new red Porsche, decide to make a 160km trip to Carolina Beach, traveling at 80km?hr. Your make a return trip at a rate of 48km?hr. What was your average speed for the entire trip?

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satellite73
 one year ago
Best ResponseYou've already chosen the best response.0figure out the total time, and the total distance divide the total distance by the total time

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0ok it was easy but i got it wrong total distance is \(2\times 160=320\)

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0time going in your new red porche is \(\frac{160}{80}=2\)

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0how about the time returning?

jdlandreth
 one year ago
Best ResponseYou've already chosen the best response.0ugh i don't know cause it comes out as a decimal?

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0much easier (believe it or not) if you leave it as a fraction

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0in other words, take \(\frac{160}{48}\) and instead of writing it as a repeating decimal, reduce it to \(\frac{10}{3}\)

jdlandreth
 one year ago
Best ResponseYou've already chosen the best response.0okay so? then do i leave the other as 2? or 160/2?

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0now the next job is to total up the time, in other words compute \[2+\frac{10}{3}\] leave it as a fraction

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0right and now speed is distance divided by rate

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0so your final job is \[320\div \frac{16}{3}\]

jdlandreth
 one year ago
Best ResponseYou've already chosen the best response.0So the average is 60?

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0that is what i get too

jdlandreth
 one year ago
Best ResponseYou've already chosen the best response.0kay good. Thank you!!

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0notice two things 1) the average speed is not the "average of the speeds" and 2) the 160 is a red herring if you really want to impress your math teacher, show that it works no matter how far you drive

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0you could drive 160 miles or 100 miles or 3,000 miles or \(m\) miles, the average will still be 60

jdlandreth
 one year ago
Best ResponseYou've already chosen the best response.0Okay Thank you soo much. =)

satellite73
 one year ago
Best ResponseYou've already chosen the best response.0try it with \(m\) you get \[\frac{2m}{\frac{m}{80}+\frac{m}{48}}=60\] after some algebra
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