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Medgirl314
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Homework Statement
A racecar driver must average 200 km/h over the course of a time trial lasting ten laps. If the first nine laps were done at 199 km/h, what average speed should be maintained for the last lap?
Homework Equations
avg =distance/time
The Attempt at a Solution
He drove at 199 for 9 laps.
199*9=1791
He needed to average 200 for 10 laps.
2000
2000-1791=209.
The answer is 209.5 km/h, but why?? I also tried dividing 199 by 9 and 200 by 10, averaging to get 21.05, and then multiplying by 10, but that isn't working either. I'm having a hard time finding an appropriate equation, so I was trying to think it through logically. It didn't work.
Thanks in advance for an answer!