Multiple choice

A car covers a certain distance in 8 hours. In order to decrease the time taken by 2 hours, how much percentage increase in speed should be there?

  1. 33%

  2. 42%

  3. 45%

  4. 35%

  5. 37%
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A Correct answer
Explanation

Let distance be D. Initial speed is D/8. New time is 6 hours, so new speed is D/6. The increase in speed is (D/6 - D/8) / (D/8) = (1/6 - 1/8) / (1/8) = (4/24 - 3/24) / (3/24) = 1/3, which is 33.33%.

AI explanation

The original time is 8 hours and the new time is 6 hours (8 - 2). Since speed and time are inversely proportional for a constant distance, the ratio of the original speed to the new speed is 6:8, which simplifies to 3:4. The required percentage increase in speed is ((4 - 3) / 3) * 100, resulting in a 33% increase.

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