Err, real easy problem but what'd he(or I) do wrong

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SUMMARY

The discussion centers on calculating the required speed to average 180 km/h over four laps of a race track, given that the average speed after two laps is only 150 km/h. The correct calculation reveals that to achieve the desired average, the driver must complete the remaining laps at a speed of 225 km/h, not the commonly assumed 210 km/h. This conclusion is derived from analyzing the time taken for each segment of the race, highlighting the importance of precise calculations in speed and time relationships.

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schattenjaeger
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the problem was that a guy wants to average a speed of 180 km/h while driving 4 laps around a race track.
after 2 laps, he's only averaged 150, so its asking what the average would have to be so that he does attain his goal.

So everybody would read the question, put 210, then check the answer in the back of the book and they would assume they are right.

But from the start i knew it wasnt what it seemed. Since If 1 lap=1 km, then going 180 km/h, it would take you 80 seconds to finish all 4 laps.

But, going 150, it would take you 48 seconds to finish 2 laps, and then going 210, it would take you roughly 35 seconds. which comes out to ~83 seconds, and not 80.

So The point is to find how fast you have to go to do a lap in 32, seconds, which comes out to 225 km/h.

When i first started explain it, no one would believe me, i felt like galileo or something


I got 210 myself, and upon close scrutinizing I can't find an error in either of our calculations, and all things considered, the inverse ability function probably made me wrong(what's the saying, you know you're a physics major when you can do vector calculus but don't remember long division?)
 
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You're correct. Can you read my working ?
 

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