Question

a plane left 30 minutes late then its scheduled time and in order to reach the destination 1500 km away in a time it had to increase its speed by 100 km per hour from the usual speed find its usual speed

Answer 1

Hey mate..

Here's your answer..

==============================

HOPE IT HELPS

@Rêyaañ11

Answer 2

Heya !!

==================================

Let the usual speed of plane be x km/hr.

A.T.Q.

1500/x – 1500/(x+100) = 30/60

=>[ 1500(x+100) – 1500x] / x(x+100) = 1/2

=> 150000 / (x²+100) = 1/2

=> x²+100 = 300000

=> x²+100–300000 = 0

=> x²+600x–500x–300000 = 0

=> x(x+600) –500(x+600) = 0

=> (x–500) (x+600) = 0

=> x = 500 or x = –600

Speed can't be negative.
So, x = –600 is inappropriate.

Thus, the usual speed of the train is 500 km/hr.

==================================

Hope my ans.'s satisfactory.☺