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Old 6th January 2011 | 19:18
  #6721 (permalink)  
boeingairbus1981
 
Joined: Jan 2011
Posts: 21
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From: manchester
Help with a distance time question

Can anyone tell me whether I'm right or wrong with this question?

2 aircraft are heading in the same direction
the cruising speed of aircraft 1 is 460 knts
the distance between aircraft is 35 nm
the 2nd aircraft passes after 21 minutes
what is the speed of the 2nd aircraft?



My solution is the difference in speed of the aircraft (v) = d/t

So v = 35 / 21 minutes
21 minutes is 7 20ths of an hour so
v = 35 / (7/20) or 35 x (20/7)
so v = 100knts

If aircraft 1 is doing 460knts and is passed by aircraft 2 and there is a speed difference of 100 knts then the speed of aircraft 2 must be 560knts

The answer given is 360knts. Ie they say aircraft 2 is 100 knots slower
How can this be if aircraft 2 passes aircraft 1 and they are heading in the same direction?
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