A circular bicycle path is 1km long. Dodi rode a bicycle for two rounds at the speed of 30kph. If he wants to average 40kph, what should be his speed for the next four rounds? 請翻成中文 並解答和過程
_________________ 數學=樂趣
2007-08-27 21:23
predictor Just popping in
註冊日: 2008-01-27 發表數: 1
Re: bicycle
1km times2=2km(first two rounds) 2km devided by 30kph=0.0666....(time he spend for the first two rounds) because average kph means all distance devided by all time so 1km times 6(all rounds)=6km 6km dvided by 40kph=0.15(all the time he should spend) 0.15-0.0666...=0.0833334... 4km devide by 0.0833334 =47.999961kph
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