Question

While boarding an aeroplane,a passenger got hurt. The pilot showing promptness and concern,made arrangement to hospitalise the injured and so the plane started late by 30 mins . To reach the destination 1500km in time , the pilot increased the speed by 100km/hr . Find the original speed of the plane

Answer 1

Step-by-step explanation:

Answer:

let the speed be x km/hr

distance given = 1500 km

time= distance/speed

T1 (time 1) =1500/x

T2 (time 2) = 1500/x+100

acc to the ques

T1-(30/60)hr    (late by 30 mins)       =          T2

=1500/x   -1/2 = 1500/x+100  

=1500/x  - 1500/x+100 = 1/2

=1500x + 1,50,000 -1500x  =  1/2

         x²+100x

=1,50,000= 1/2 X ( x²+ 100x )

2 X 1,50,000 = x² + 100x

3,00,000 = x² + 100x

x² + 100x - 3,00,000 = 0

splitting the middle term

x² + 600x -500x -3,00,000 = 0

x ( x + 600 ) - 500 ( x + 600 ) = 0

( x - 500 ) ( x + 600 ) = 0

x = 500   or     x =  - 600

since speed cannot be negative hence we consider  x = 500

therefore x = original speed = 500 km/hr