1) An aeroplane flies at an average speed of 950km/h from P to Q and back. P and Q are 1140 km apart. Find the flying time.
2) Mr Chan drives between A and B. He drives to A at a speed of 80 km /h. He drives to B at a speed of 60 km/h The two cities are 144 km apart. Find the total time in the two journeys.
23) A and B drive at the same time from the same place towards the same place. Their speeds are 75 km/h and 68km/h respectively.How far ahead will A be after l h 45 min?
數學題請教列式
2007-07-23 9:06 pm
回答 (2)
2007-07-23 9:17 pm
✔ 最佳答案
1) (1140 x 2) / (950 x 2) = 1.2hour2) 144 / (80+60) = 1.028571 hour
3) (75 - 68) x 1.75 = 12.25 km
2007-07-23 9:35 pm
1.
1140 x 2 = total distance of the travel
Distance / speed = time
1140 x 2 / 950
2.
Distance / speed = time
Time 1 + Time 2 = total time
144 / 80 + 144 / 60
3.
Speed of A = 75km/h
Speed of B = 68km/h
1h 45min = 1.75h
75x1.75 = total distance of A travel in 1.75h
68x1.75 = total distance of B travel in 1.75h
75x1.75 – 68x1.75
2007-07-25 08:05:39 補充：
第一及二條錯左
1140 x 2 = total distance of the travel
Distance / speed = time
1140 x 2 / 950
2.
Distance / speed = time
Time 1 + Time 2 = total time
144 / 80 + 144 / 60
3.
Speed of A = 75km/h
Speed of B = 68km/h
1h 45min = 1.75h
75x1.75 = total distance of A travel in 1.75h
68x1.75 = total distance of B travel in 1.75h
75x1.75 – 68x1.75
2007-07-25 08:05:39 補充：
第一及二條錯左
收錄日期: 2021-04-23 17:08:03
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