A train travels a distance of 480 km at a uniform speed if the speed had been 8 km less than it would have taken 3 hours more to cover the same distance find the speed of the train
Answers
(i) Let us consider,
The breadth of the rectangular plot is x m.
Thus, the length of the plot = (2x + 1) m
As we know,
Area of rectangle = length × breadth = 528 m2
Putting the value of length and breadth of the plot in the formula, we get,
(2x + 1) × x = 528
⇒ 2x^2 + x = 528
⇒ 2x^2 + x – 528 = 0
Hence, 2x2 + x – 528 = 0, is the required equation which represents the given situation.
(ii) Let us consider,
speed of train = x km/h
And
Time taken to travel 480 km = 480 (x) km/h
As per second situation, the speed of train = (x – 8) km/h
As given, the train will take 3 hours more to cover the same distance.
Therefore, time taken to travel 480 km = (480/x) + 3 km/h
As we know,
Speed × Time = Distance
Therefore,
(x – 8)[(480/x) + 3] = 480
⇒ 480 + 3x – (3840/x) – 24 = 480
⇒ 3x – (3840/x) = 24
⇒ 3x^2 – 24x – 3840 = 0
⇒ x^2 – 8x – 1280 = 0