Question

A train takes 2 hours less for a journey of 300km if its speed is increased by 5 km/h from its
usual speed. Find the usual speed of the train.

Answer 1

Answer:

25 km/hr

Step-by-step explanation:

Usual speed = x km/hr

Increased speed = x+5 km/hr

Usual time = 300/x

Reduced time = 300/(x+5)

300/x - 300/(x+5) = 2

300 (x+5) - 300x = 2x(x+5)

1500 = 2(x^2 + 5x)

x^2 + 5x -750 = 0

x^2 +30x -25x -750 = 0

(x+30)(x-25) = 0

x = 25 as x =-30 is not possible speed can not be negative

So usual speed = 25 km/hr

Answer 2

let speed of train =x km/hr.
distance =300 km
time =2hr. less
by 1st cond.
300/x-------1
by 2nd cond.
300/x+5-----2
sub. 2nd from 1st
the answer in the photo