Multiple choice

A person travels a certain distance with 3.5 km/hr. Had he increased his speed by 100%, he would have travelled 21 km more in the same time. Find the distance travelled by him.

  1. 21 km

  2. 42 km

  3. 45 km

  4. 35 km

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Initial speed = 3.5 km/hr. New speed = 3.5 + 100% of 3.5 = 7 km/hr. Let time be T. Distance D = 3.5T. New distance D + 21 = 7T. Subtracting: 21 = 3.5T. T = 6 hours. D = 3.5 * 6 = 21 km.

AI explanation

An increase of 100% on a speed of 3.5 km/hr doubles the speed to 7 km/hr. Let the usual time be t hours, so the original distance is 3.5 multiplied by t. In the same time t, the new distance covered is 7 multiplied by t, which is stated to be 21 km more than the original distance. This gives the equation 7t - 3.5t = 21, meaning 3.5t equals 21. The actual distance travelled by him is 3.5 times 6, which equals 21 km.

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