數學題..唔該-333333333333-'''

2008-03-19 6:35 am

系咁既↘
陳先生駕車的速率是60km/h,黃小姐駕車的速率是80km/h.兩車同時同地同向而行,要多久兩車才會相隔15公里.
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回答 (3)

2008-03-19 6:39 am

✔ 最佳答案

1h 相隔20公里
so 15/20=3/4
1h=60min
60*3/4=45min會相隔15公里

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2008-03-19 6:44 am

Let T be the time needed.
80km/h x T - 60km/h x T = 15km
20T=15
T= 0.75 hr
T= 45min
Therefore, it needs 45minutes to meet each other.

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2008-03-19 6:38 am

80km/h x T - 60km/h x T = 15km

20T=15
t=3/4hr = 0.75 hr
= 45min

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