Multiple choice

The winning relay team in a high school sports competition clocked 48 minutes for a distance of 13.2 km. Its runners A, B, C and D maintained speeds of 15 kmph, 16 kmph, 17 kmph and 18 kmph, respectively. What is the ratio of the time taken by B to that taken by D?

  1. 5 : 16

  2. 5 : 17

  3. 9 : 8

  4. 8 : 9

  5. 9 : 15
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The distance for each runner is not explicitly stated as equal, but in a relay, they cover the total distance. However, the question asks for the ratio of time taken by B and D. Time = Distance / Speed. Since they run the same distance (13.2 km / 4 = 3.3 km each), the ratio of time is (1/16) : (1/18) = 18 : 16 = 9 : 8.

AI explanation

Since distance equals speed multiplied by time, the time taken is inversely proportional to the speed when the distance is constant. The ratio of the time taken by B to the time taken by D equals the inverse ratio of their speeds, giving 18 : 16 or 9 : 8. The total time of 48 minutes and the total distance of 13.2 km are not needed for this specific ratio.

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