Question

While boarding an aeroplane a passenger got hurt The pilot showing
promptness and concern made arrangements to hospitalise the injured and
so the plane started late by 30 minutes to reach the destination, 1000 km
away the pilot increased the speed by 100 km/hr.What is the original speed of train?​

Answer 1

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