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Question
An aeroplane leaves an airport and flies due north at a speed of 1000km/hr. At the same time, another aeroplane leaves the same airport and flies due west at a speed of 1200 km/hr. How far apart will be the two planes after 1 hours?
Solution
Distance traveled by the plane flying towards north in `1 1/2`hrs
`= 1000xx1 1/2=1500`km
Similarly, distance travelled by the plane flying towards west in `1 1/2`hrs
`=1200xx1 1/2=1800`km
Let these distances are represented by OA and OB respectively.
Now applying Pythagoras theorem
Distance between these planes after `1 1/2`hrs AB `=sqrt(OA^2+OB^2)`
`=sqrt(1500^2+1800^2)`
`=sqrt(2250000+3240000)`
`=sqrt5490000`
`=sqrt(9xx610000)`
`=300sqrt61`
So, distance between these planes will be `300sqrt61` km, after `1 1/2`hrs
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