Question

A plane left 30 min late than its schedule time and in order to reach the destination 1500km away in time it had to increase its speed by 100km/have from its usual speed find its usual speed

Answer 1

500kmph.............

Answer 2

hi..

SOLUTION:-
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1●Let the usual time taken by the aeroplane = .........x km/hr

given..

●Distance to the destination = 1500 km

then,
acourding to quetion,

speed= distantance/time

= time= (1500/x)hrs........eq.(1)

similarly give...

●Time taken by the aeroplane = (x - 1/2) Hrs

●Distance to the destination = 1500 km

●Speed = Distance / Time = 1500 / (x - 1/2) Hrs

●increased speed= 100km/h

then... create equetion is...

1500 / (x - 1/2)] - [1500 / x] = 1

= 15/(x-1/2) - [ 15/x] = 1
= 1/(x-1/2) - 1/x = 1/15
=  1/(2x2 - x) = 1/15
= 2x^2 - x - 15= 0

= 2x^2 -6x+5x -15= 0
= 2x(x-3) + 5(x-3) = 0

= (x-3)(2x+5) = 0
= x = 3 ,[ x = - 5/2 does not exit]

The usual time taken by the aeroplane = 3 hrs
and the usual speed = (1500 / 3) = 500 km/hr.


i hope it is helpfull for u