A car travels a distance of 60 km at uniform speed. If the speed of car is increased by 8 km/hr, then it takes 2 hours less to cover the same distance. What is the original speed of the car?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 12 km/hr.
Let the original speed of the car = x km/hr
(60/x) - [60/(x + 8)] = 2
⇒ (30x + 240 - 30x)/(x2 + 8x) = 1
⇒ 240/(x2 + 8x) = 1
⇒ x2 + 8x - 240 = 0
⇒ (x + 20)(x - 12) = 0
⇒ x = - 20 or 12
Hence, the original speed of the car is 12 km/hr.