Multiple choice

Ratio of speeds of three cars is 3 : 6 : 8. Calculate the ratio of time taken by these cars, if they cover the same distance.

  1. 4 : 8 : 3

  2. 3 : 8 : 4

  3. 8 : 4 : 3

  4. 8 : 3 : 4

  5. 4 : 3 : 8
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C Correct answer
Explanation

Since speed is inversely proportional to time for a constant distance, the ratio of time taken is the inverse of the ratio of speeds. The inverse of 3:6:8 is 1/3 : 1/6 : 1/8. Multiplying by the least common multiple (24) gives 8 : 4 : 3.

AI explanation

Using the formula Time = Distance / Speed, when the distance covered is constant, time taken is inversely proportional to speed. The ratio of speeds is 3 : 6 : 8, so the inverse ratio is 1/3 : 1/6 : 1/8. Multiplying by the least common multiple of 24, we get the ratio of times as 8 : 4 : 3. The ratio of time taken by these cars is 8 : 4 : 3.

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