Question

a train takes one hour less for a journey of 150 km if its speed increased by 5 km/hr from its usal speed find speed of train

Answer 1

Heyaa user!!!
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Here's your answer :-

Let the usual speed of the train be x kmph....

Distance =150km.....

Then,

Time taken to cover the distance with this sped =(Distance /speed)

=(150/x)hr...........

Now, Increased speed =(x+5)kmph...

Time taken to cover 150km with this speed =(150/x+5)hr...

Acc. To question,

150/x-150/(x+5)=1

=>150(x+5)-150x/x(x+5)=1

=>150x+750-150x/x²+5x=1

=>x²+5x=750

=>x²+5x-750=0

=>x²+30x-25x-750=0

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

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

=>x=25,-30

Hence speed can't be in negative, we take the positive value of x....

Therefore usual speed of the train =25kmph.....

Hope this helps!!!

Good luck :-)