Multiple choice

A bus travels a certain distance in 40 minutes, if it runs at a speed of 60 km/hr on an average. Find the speed (in km/hr) at which the bus must run to reduce the journey time to 20 minutes.

  1. 50

  2. 120

  3. 55

  4. 80

  5. 70
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Distance = Speed * Time = 60 km/hr * (40/60) hr = 40 km. To cover 40 km in 20 minutes (1/3 hr), the required speed = Distance / Time = 40 / (1/3) = 120 km/hr.

AI explanation

The total distance of the journey is calculated by multiplying the initial speed by the time in hours: 60 km/hr multiplied by (40/60) hours equals 40 km. To cover this 40 km distance in 20 minutes, which is 1/3 of an hour, the required speed is distance divided by time. This gives 40 km divided by (1/3) hr, resulting in a required speed of 120 km/hr.

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