Question

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

Answer 1

Answer:

40 km/hr

Step-by-step explanation:

Distance traveled by train = 360 km.

(i)

Let the speed of the train be 'x' km/hr.

We know that Speed = Distance/Time

                                   = 360/x.

(ii)

Given that Speed of the train is increased by 5 km/hr.

Increased speed = (x + 5) km/hr.

Speed = 360/x + 5.

Given that Time taken is 1 hour less when compared to the previous time.

⇒ (360/x) - (360/x + 5) = 1

⇒ 360(x + 5) - 360x = x(x + 5)

⇒ 360x + 1800 - 360x = x² + 5x

⇒ 1800 = x² + 5x

⇒ x² + 5x - 1800 = 0

⇒ x² + 45x - 40x - 1800 = 0

⇒ x(x + 45) - 40(x + 45) = 0

⇒ (x - 40)(x + 45) = 0

⇒ x = 40, -45.

Since, Speed is a non-negative term, therefore x ≠ -45.

⇒ x = 40.

Therefore, Speed of the train = 40 km/hr.

Hope it helps!

Answer 2

Answer:

40

Step-by-step explanation:

If train travel at a speed of 40 km/h then it takes 9 hour for complete 360 km. Now if u increased speed 5km/h more. Then its take 8 hour for complete 360 km. As your quiestion it would have taken 1 hour less to complete the same journey.

360km÷40km/h=9hour.

360km÷(40+5)km/h=8hour.

So the answer is 40 km/h.