好急!2 MATHS

TszYing

2007-11-28 6:25 am

1)A plane was detected at 6000m right above observation post A.20 seconds later,the plane was detected at 5000m right above observation post C.Given that the two observation posts were 2400m apart,what was the speed of the plane in km per hour?(Suppose the plane was travelling in a straight line.)

更新1:

2)The figure shows a swimming pool of length 50m,width 20m and depths 1.5m and 5m at the two wnds. Given that the area of a tile is 0.25m^2,how many tiles are needed to cover the bottom of the swimming pool?(Given the answer correct to the nearest integer.)

回答 (2)

用戶46949

2007-11-28 7:20 am

✔ 最佳答案

1)
the distance travel = sqrt ( 1000^2 + 2400^2)
=2600m = 2.6 km

the speed = 2.6 / [ 20/ (60 * 60) ] = (2.6 )(3600) /20
= 468 km per hour //

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ting

2007-11-28 6:52 am

for..Q1 2400/1000 / 20/60
distance / time

for Q2 50X20 / 0.25........

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