UPSC One
Back to the full 2013 paper
2013 · Q5

If a body covers a distance at the rate of x km/hr and another equal distance at the rate of y km/hr, then the average speed in km/hr is

Elementary MathematicsArithmetic
  1. A(x+y)/2
  2. B√xy
  3. C2xy/(x+y)
  4. D(x+y)/xy

Explanation

Harmonic mean for equal distances: 2xy/(x+y). Answer C.