A vehicle is going at one-fourth of its usual speed and it takes an extra 45 minutes to reach its destination. Its usual time to cover the same distance is:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 15 minutes.
When distance is constant
Speed is inversely proportional to time
Let the usual speed be 4x
New speed = 1/4 of 4x = 1x
Ratio of speed (New speed : usual speed) = 1x : 4x
The ratio of time taken (New time : usual time) = 4x : 1x
According to the question;
⇒ 4x - x = 45
⇒ 3x = 45
⇒ x = 15
Hence, the required usual time taken = x = 15 mins