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  • A train travels 360 km at a uniform speed. If the speed had been 5 km/h more, it would have taken 1 hour less for the same journey. Find the speed of the train.

Q8.    A train travels 360 km at a uniform speed. If the speed had been 5 km/h more, it would have taken 1 hour less for the same journey. Find the speed of the train.

Answers (1)

best_answer

As we know that 

speed=\frac{distance}{time}

Let the distance x and time taken be t. 

Now According to the question,

v=\frac{360}{t}........(1)

And

v+5=\frac{360}{t-1}........(2)

From (1) we have

t=\frac{360}{v}..........(3)

Putting this on (2), we get

v+5=\frac{360}{\frac{360}{v}-1}

(v+5)(360-v)=360v

360v-v^2+1800-5v = 360v

v^2+5v-1800 = 0

v^2-40v+45v-1800 = 0

(v+45)(v-40)=0

v=40 \:or\:-45

Since speed can never be negative, we choose,

v=40 \:km/h

Hence the speed of the train is 40 km/hour.

 

Posted by

Pankaj Sanodiya

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