Multiple choice

The effective speed of travel of a boat downstream is 20 kmph whereas it is 10 kmph upstream. What is the speed of the current?

  1. 10 kmph

  2. 8 kmph

  3. 5 kmph

  4. 2.5 kmph

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

Let boat speed be B and current speed be C. Downstream speed = B + C = 20. Upstream speed = B - C = 10. Subtracting the equations: (B + C) - (B - C) = 20 - 10 => 2C = 10 => C = 5.

AI explanation

Using the formula for the speed of the current, speed of stream equals half the difference of downstream and upstream speeds. Substituting the given values gives half of 20 minus 10, which equals 5 kmph. The speed of the current is 5 kmph.

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