Multiple choice

A car travelling at an average speed of 72 km/hr takes 9 minutes to travel a certain distance. By how much should it increase its speed (in km/hr) to travel the same distance in 8 minutes?

  1. 8

  2. 9

  3. 7

  4. 6
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Distance = 72 km/hr * (9/60) hr = 10.8 km. New speed required = 10.8 km / (8/60) hr = 10.8 * 7.5 = 81 km/hr. Increase = 81 - 72 = 9 km/hr.

AI explanation

Using the formula Speed equals Distance divided by Time, the distance is 72 multiplied by (9/60), which equals 10.8 km. To travel this distance in 8 minutes, the required speed is 10.8 divided by (8/60), which equals 81 km/hr. The required increase in speed is 81 minus 72, which equals 9 km/hr.

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