A thief committed a crime and escaped from the spot at a speed of 12 m/h. A Security guard started chasing him 20 minutes after the thief started running and caught him in the next 20 minutes. What is the speed (in m/h) of the Security guard?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 24.
We know that
Distance = Speed × Time
Calculation:
In the 1st 20 min the thief cover distance = 4 m,
20 min in hour = 20/60 hour
Let's assume that the speed of the security guard = x m/hr, where x > 12
According to the question,
⇒ (x - 12) × 20/60 = 4
⇒ x - 12 = 12
⇒ x = 24