Question 461967: Hi all. My question is this.
"Two aircraft heading in the same direction. Only the cruising speed of the first aircraft is known, 230mph. Distance between both aircraft is 24 miles. The second aircraft passes the first after 18 minutes. What is the speed of the second aircraft?
Straight forward enough.. the "difference" in speed is 80mph between both aircraft, because Speed is Distance/Time. So I add 80mph to 230mph = 310mph the speed of the second aircraft.
However...the answer is 230mph - 80mph = 150mph! Huh? Common sense dictates that to pass one moving object you MUST be moving faster than said object by x amount, not travelling slower!
Am I missing something here? or is the answer wrong!
Confused regards Pete..
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! "Two aircraft heading in the same direction. Only the cruising speed of the first aircraft is known, 230mph. Distance between both aircraft is 24 miles. The second aircraft passes the first after 18 minutes. What is the speed of the second aircraft?
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It takes the 2nd aircraft 18 minutes to make up
the 24 mile difference in their positions.
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rate = distance/time
rate = 24 miles/(18/60) hrs
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rate = 24*(60/18) = 24(10/3) = 80 mph
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The 2nd aircraft is going 80 mph faster than the 1st
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rate of 2nd aircraft = 230+80 = 310 mph
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Cheers,
Stan H.
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