Question

An aeroplane leaves an airport and flies due north at a speed of 1000 km per hour. At the same time, another aeroplane leaves the same airport and flies due west at a speed of 1200 km per hour. How far apart will be the two planes after 1 1/2 hours?

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Answer 1

distance of first aeroplane in 1 1/2 hours

= 1000 + 500

= 1500

distance of second aeroplane in 1 1/2 hours

= 1200 + 600

= 1800

so,

let us consider the starting point be A and the distance reached by 1st and 2nd aeroplane is B and C

so we know AB and BC we have to find AC

(AB)^2 + (BC)^2 = (AC)^2

(1500)^2 + (1800)^2 = (AC)^2

(2250000) + (3240000) = (AC)^2

5490000 = (AC)^2

AC = root of 5490000

= 234.3074902772 km

= 234.31 km

think so this may help you ....