Jim Henderson wrote:
> On Wed, 20 Jan 2010 08:11:28 -0800, Darren New wrote:
> 
>> Warp wrote:
>>>   I have hard time parsing that question.
>> It *is* messed up. The usual question is something like
>>
>> You have a race two miles long. For the first mile, one car goes 60MPH
>> and the other goes 30MPH. How fast does the other car have to go to
>> finish the race at the same time as the one going 60MPH?
> 
> Even then it doesn't parse correctly, because they've given you the 
> speeds for both cars - so asking how fast the slower car should go 
> doesn't make sense, because you've been told how fast it is going.

The race is two miles long. The slow car goes at a speed for one mile. 
What's the speed in the second mile?

(I guess I left out that the fast car keeps going the same speed.)

> And I'm not sure that discarding the length of the track allows the 
> question to be answered even then. 

No, that would eliminate the ability to answer.

Anyway, that's an easy question to answer. A slightly better version is this:

You want to average 60MPH over two minutes. You go 30MPH for the first mile. 
How fast do you have to go to average 60MPH for two minues?

Second alternate question: you want to average 60 MPH. You drive 10 miles at 
30MPH. How many miles do you need to drive at 90MPH to average 60MPH?

-- 
Darren New, San Diego CA, USA (PST)
   Forget "focus follows mouse." When do
   I get "focus follows gaze"?

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