Question

(ii) If the speed of a car is decreased by 8 km/h, it takes 1 hour more to cover a
distance of 240 km. Find the original speed of the car.

Answer 1

Answer:

30 km/h

Step-by-step explanation:

hope it's helpful for you

Answer 2

Let the original velocity of the car be 'x' kmph.

 Time taken to cover 240 km:

⇒ x = 240/time

⇒ time = 240/x          

When speed is decreased by 8: time increases by 1,

⇒ (x - 8) = 240(time + 1)

⇒ time + 1 = 240/(x - 8)

⇒ (240/x) + 1 = 240/(x - 8)

⇒ (240 + x)/x = 240/(x - 8)

⇒ (240 + x)(x - 8) = 240x

⇒ 240x - 1920 + x² - 8x = 240x

⇒ x² - 8x - 1920 = 0

⇒ x² - 48x + 40x - 1920 = 0

⇒ (x + 40)(x - 48) = 0

   x = 48,    ∴ speed of the car is 48 kmph