πŸ“’ Too many exams? Don’t know which one suits you best? Book Your Free Expert πŸ‘‰ call Now!

  • google app store apple app store
  • βœ–

      Question

      The speed of current is 9 km/h. What will be the

      respective downstream speed and upstream speed of a boy rowing a boat, if one seventh of the distance covered going downstream in a certain time is equal to the distance covered going upstream in the same time?
      A 21 km/h, 3 km/hr Correct Answer Incorrect Answer
      B 27 km/h, 9 km/hr Correct Answer Incorrect Answer
      C 20 km/h, 10 km/hr Correct Answer Incorrect Answer
      D 16 km/h, 4 km/hr Correct Answer Incorrect Answer
      E None of these Correct Answer Incorrect Answer

      Solution

      Let the speed of boy in still water be X km/h. And the speed of current = 9 km/h Downstream speed = (X + 9) km/h Upstream speed = (X – 9) km/h Let time be ‘t’ hours. ⇒ [(X + 9) t]/7 = (X – 9) t ⇒ X + 9 = 7X – 63 ⇒ X = 12 km/h Downstream speed = 12 + 9 = 21 km/h Upstream speed = 12 – 9 = 3 km/h

      Practice Next

      Relevant for Exams:

      ask-question