Question

An aeroplane leaves an airport and flies due north at a speed of 1000 km per hour. How far apart will be the two planes after 3/2 hours?

Answer 1

which two plane here you have mentioned about only one

Answer 2

. 

Distance travelled by aeroplane in 3/2 hours towards north direction = 1000*3/2

                                                                                                        = 500*3

                                                                                                        = 1500 km

So AB = 1500

Distance travelled by aeroplane in 3/2 hours towards north direction = 1200*3/2

                                                                                                        = 600*3

                                                                                                        = 1800 km

So BC = 1800

Now from Pythagorus theorem

      AC2 = AB2 + BC2

=> AC2 = (1500)2 + (1800)2

=> AC2 = 2250000 + 3240000

=> AC2 = 5490000

=> AC = √5490000

=> AC =√(32 * 1002 * 61)

=> AC = 3*100* √61

=> AC = 300√61 

So distance between two planes after 3/2 hours = 300√61 km