If the speed of a car is decreased by 12 km/h, it takes 1 hour more to cover a
distance of 240 km. Find the original speed of

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1. Answer:

   Step-by-step explanation:

   Let the speed of the car be x km per hour

   Distance = 240 km

   Speed of car = x km per hour

   Time = Distance/speed

   Time = 240/x

   If the speed of the car is decreased by 8 km per hour, it takes 1 hour more to cover a distance of 240 km

   Time during changed speed

   = 240 km /x – 8 km per hour

   240/(x – 8) – 240/x = 1 hour

   240x —240 (x – 8)/ x (x – 8) = 1 hour

   240x — 240x + 1920/ x^2 – 8x = 1 hour

   1920/x^2 – 8x = 1 hour

   Cross multiplication

   x^2 – 8x = 1920

   x^2 – 8x -1920 = 0

   x^2 – 48x + 40 x – 1920

   x (x – 48) + 40 (x – 48)

   (x + 40) (x – 48)

   x = —40 is not possible being negative hence discarded

   x = 48 km per hour

   The original speed of the car was 48 km per hour

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