A car travels a distance of 300 kms at uniform speed. If

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A car travels a distance of 300 kms at uniform speed. If the speed of the car is 5 km per hr more it takes two hours less to cover the same distance. Find the original speed of the car.

1. 25 kmph
2. 20 kmph
3. 24 kmph
4. 28 kmph

Correct Option: A

Let the original speed of the car = x km per hr.
When it is increased by 5 km
per hr, the speed = x + 5 km per hr.
As per the given information in the question,

300	−	300	= 2
x		x + 5

⇒	300(x + 5) − 300x	= 2
	x(x + 5)

⇒	300x + 1500 − 300x	= 2
	x² + 5x

⇒	1500	= 2
	x² + 5x

⇒	750	= 2
	x² + 5x

⇒ 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 = – 30 or 25
The negative value of speed is inadmissible.
Hence, the required speed = 25 km per hr.