Another Math Question
Nov 28, 2008 at 5:29 AM Thread Starter Post #1 of 6

Endzone

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A car is driving along a road and begins to go up a hill that is perfectly symetric and exactly 1 mile long from start to finish. If the car averages 30MPH up the first 1/2 mile of the hill, what must be its average downhill speed in order to average 60MPH for the entire mile?

INCORRECT Answer: 90MPH
 
Nov 28, 2008 at 5:41 AM Post #2 of 6

Zodduska

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88mph in a DMC equipped with a flux capacitor so it can travel back in time to re-drive the first 1/2 at 60mph? ugh my head hurts, I give up
wink.gif
 
Nov 28, 2008 at 5:44 AM Post #3 of 6

Arainach

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I fail to see why this question deserves its own thread.

Driving half a mile at 30 takes a minute. To average 60 over a mile means you must drive a mile in a minute. It is impossible for the car to average 60.
 
Nov 28, 2008 at 5:46 AM Post #5 of 6

Fuzzy OneThree

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SPOILER HIGHLIGHT OVER:


It cannot average 60 MPH. In order to average 60 MPH, it must go 1 mile in one minute (60 miles in 60 minutes). It takes 1 minute to go 1 mile at 60 MPH, but at 30 MPH, it will take 1 minute to go 1/2 mile. So, there is no speed that will make it average 60 MPH.
 
Nov 28, 2008 at 7:16 AM Post #6 of 6

Endzone

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Quote:

Originally Posted by Arainach /img/forum/go_quote.gif
I fail to see why this question deserves its own thread.

Driving half a mile at 30 takes a minute. To average 60 over a mile means you must drive a mile in a minute. It is impossible for the car to average 60.



Haha. A little more humility for you please. You act like you didn't even have to think about it to get the right answer. But the right answer you did get.

You can't handle the orthographic projection question, or did you already see Zodduska's answer?
 

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