Question

a train takes 2 hours less for a journey of 300km if its speed is increased by 3 kmh from usual speed find the usual speed of train​

Answer 1

${\huge {\mathfrak {\orange {Answer :-}}}}$

➡️ There is a mistake in the question, the speed increases by 5 km/h, not by 3 km/h. Please correct it. ⬅️

$<b>$ Let the usual speed of the train be x km/h.

Thus, it will take time = distance / speed

= 300 / x.

When, the speed is increased by 5 km/h, it will take time

= distance / speed

= 300 / (x + 5)

Given, that the train takes 2 hours less.

So, we have,

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

Or, [300(x + 5) - 300(x)] / x(x + 5) = 2

Or, 300x + 1500 - 300x = 2 (x^2 + 5x)

Or, x^2 + 5x = 1500 / 2 = 750

Or, x^2 + 5x - 750 = 0

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

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

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

Or, x = 25, - 30

Speed cannot be negative, so

Speed = 25 km/h.

➡️ Hence, the usual speed of the train was 25 km/h. $</i>$

$<i>That's it.. </i>$

${\red {-:Arnab \: here :-}}$
$<marquee >$
${\huge {\blue {Thanks}}}$

Answer 2

Answer:

Step-by-step explanation: