A train travels a distance if 480km at a uniform speed. If the speed had been 8km/h less,then it would have taken 3 hours more to cover the same distance . We need to find the speed of the train
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Let the speed of train be "x" km/hr
So as we know speed = distance / time
or time = distance / speed
So now we have the following
As the speed is reduced by 8 km / hr , we have new speed = x - 8 km/hr.
So the difference of original time and new time to reach its destination is 3 hrs.
It can be represented as:-
480/x - 480/x-8 = 3
480(x - 8 - x / x^2 - 8x) = 3
By solving the above quadratic equation , we get
x^2 - 8x - 1280 = 0
x^2 - 40x + 32x -1280 = 0
Hence x = -32 or 40 km/hr
As speed cant be negative,
x = 40 km/hr
HOPE IT HELPS .
ALL THE BEST!
So as we know speed = distance / time
or time = distance / speed
So now we have the following
As the speed is reduced by 8 km / hr , we have new speed = x - 8 km/hr.
So the difference of original time and new time to reach its destination is 3 hrs.
It can be represented as:-
480/x - 480/x-8 = 3
480(x - 8 - x / x^2 - 8x) = 3
By solving the above quadratic equation , we get
x^2 - 8x - 1280 = 0
x^2 - 40x + 32x -1280 = 0
Hence x = -32 or 40 km/hr
As speed cant be negative,
x = 40 km/hr
HOPE IT HELPS .
ALL THE BEST!
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