fill ups3.om/s×s= km/hr×hr
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Let the actual speed of the car be x
Actual Time taken by the car = 240/x
If he increases the speed by 20km/hr
speed = x + 20
Time taken = 240/ x+ 20
According to the question
240/x - 240/ x+ 20 = 1
240 [ 1 /x - 1/ x+ 20] = 1
240 [ x + 20 - x/x2 +20x ] = 1
240 * 20 = x2 +20x
x2 +20x - 4800 = 0
x2 +80x - 60x - 4800 = 0
x (x + 80) -60 (x+ 80) = 0
(x -60) (x + 80) =0
x = 60 or x = -80
But speed cant be negative
Thus x = 60 km/hr
Actual Time taken by the car = 240/x
If he increases the speed by 20km/hr
speed = x + 20
Time taken = 240/ x+ 20
According to the question
240/x - 240/ x+ 20 = 1
240 [ 1 /x - 1/ x+ 20] = 1
240 [ x + 20 - x/x2 +20x ] = 1
240 * 20 = x2 +20x
x2 +20x - 4800 = 0
x2 +80x - 60x - 4800 = 0
x (x + 80) -60 (x+ 80) = 0
(x -60) (x + 80) =0
x = 60 or x = -80
But speed cant be negative
Thus x = 60 km/hr
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