Question

a train takes 2 hours less for a journey of 300 km if its speed increases by 5 kilometre per hour for its use a usual speed find the usual speed of the train

Answer 1

Answer: yo!

here you go , friend!

hope to help ya out!

Step-by-step explanation:

let the usual speed be x

WKT

t=d/s

Case1

T1=d1/s1= 300/ x

Case2

T2=d2/s2=300/(x+5)

Given , t1-t2=2hrs

Therefore,

From our findings,

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

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

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

1500 = 2x^ + 10x

750= x^2 + 5x

x^2+ 5x - 750 = 0

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

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

.: .: x= 25 or x= -30

since x = usual speed

and speed cannot be negetive

x= 25 is correct

.: usual speed = 25km/hr

I dont know what made me to type it all and help you out..

bug hope it does help you(;

Answer 2

Answer:

Let the usual speed of the train be y km / hr .

A.T.Q.

$\displaystyle{\frac{300}{y} -\frac{300}{y+5} =2 }$

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

y² + 5 y - 750 = 0

y² + 30 y - 25 y - 750 = 0

( y + 30 ( y -25 ) = 0

y = - 30 or y = 25

Since , speed of train can't be negative .

Therefore , the usual speed of the train is 25 km / hr .