1) A and B drive towards each other from P and Q . Their speed are 72 km/h and 63 km/h respectively. The distance between P and Q 300 KM. A) How far apart will the two cars be after 2 hours? (b) When will they meet? C) Where will they meet (from P)?
2) A sportsman finishes a 1000-metre race in 2 min 20 seconds. What is his average speed per second?
3) Mr Wong drives at an average speed of 80 km/h from A to B. He spends 1 hour and 15 minutes. Find the distance between A and B.
數學題列式-幫下忙
2007-07-25 12:15 am
回答 (2)
2007-07-25 2:28 am
✔ 最佳答案
2) A sportsman finishes a 1000-metre race in 2 min 20 seconds. What is his average speed per second?2min20seconds:
=140seconds
1000/140
=7.1429metre per second
3) Mr Wong drives at an average speed of 80 km/h from A to B. He spends 1 hour and 15 minutes. Find the distance between A and B.
1 hour and 15 minutes:
=1 1/4hour
80x1 1/4
=100km
2007-07-25 12:28 am
I help you with 1)
2), 3) you can try yourself.
1A)
After 2 hours A will travel 72X2=144km, B will travel 126km
So after 2 hours, they will be 300-144-126=30km apart
1B)
Let X be the time taken for A and B meet
72X+63X=300
135X=300
X=2.22
X=2hours 13mins and 20seconds
1C)
Assume A starts from P, then after 2.22hrs, A will travel
72X2.22=160km (160km from P)
2007-07-24 16:30:54 補充：
just remember the speed trianglespeed=distance/time
2), 3) you can try yourself.
1A)
After 2 hours A will travel 72X2=144km, B will travel 126km
So after 2 hours, they will be 300-144-126=30km apart
1B)
Let X be the time taken for A and B meet
72X+63X=300
135X=300
X=2.22
X=2hours 13mins and 20seconds
1C)
Assume A starts from P, then after 2.22hrs, A will travel
72X2.22=160km (160km from P)
2007-07-24 16:30:54 補充：
just remember the speed trianglespeed=distance/time
收錄日期: 2021-04-23 17:08:53
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