问题1 解答: 250 s

来源: noliar 于 2008-10-03 20:40:48 [] [旧帖] [给我悄悄话] 阅读数 : (351 bytes)

思路示意图:
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total time: T,
waling time is the same as driving time (both are T).so walked distance is T.
walking time: T
driving time: 3(1000-T)/10 + T/10;

solve T = 3(1000-T)/10 + T/10.

solution: T = 250 s

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