Another Math Question
Nov 28, 2008 at 5:29 AM Thread Starter

Endzone

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?

Nov 28, 2008 at 5:41 AM

Zodduska

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

Nov 28, 2008 at 5:44 AM

Arainach

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

ZephyrSapphire

45?

Nov 28, 2008 at 5:46 AM

Fuzzy OneThree

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