Multiple choice

The speed of a boat along the stream is 12 kmph and against the stream is 8 kmph. The time taken by the boat to sail 72 km in still water. एक नाव की धारा के अनुदिश चाल 12 किमी./घंटा है और धारा के प्रतिकूल चाल 8 किमी./घंटा है | नाव द्वारा शांत जल में 72 किमी. की दूरी को तय करने में लिया गया समय है

  1. 6 hours/घंटे

  2. 9 hours/घंटे

  3. 7.2 hours/घंटे

  4. 3.6 hours/घंटे
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Speed of boat in still water = (downstream speed + upstream speed) ÷ 2 = (12 + 8) ÷ 2 = 10 kmph. Time = Distance ÷ Speed = 72 ÷ 10 = 7.2 hours. Options A, B, and D are incorrect calculations.

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