Multiple choice

A car after covering ½ of a journey of 100 km develops engine trouble and later travels at ½ of its original speed. As a result, it arrives 2 hours late than its normal time. What is the normal speed of the car is?

  1. 50 kmph

  2. 40 kmph

  3. 30 kmph

  4. 25 kmph
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D Correct answer
Explanation

Normal time = 100/v. First half (50km) at speed v takes 50/v. Second half (50km) at v/2 takes 100/v. Total time = 50/v + 100/v = 150/v. Difference: 150/v - 100/v = 2. 50/v = 2, so v = 25 kmph.

AI explanation

Half of the 100 km journey is 50 km, and if the normal speed is x, the delayed speed is x/2, making the time difference 50/(x/2) minus 50/x equal to 2 hours. This simplifies to 100/x minus 50/x equaling 2, so 50/x equals 2. Solving for x gives a normal speed of 25 kmph.

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