2026 · Q94
A cyclist pedals from her house to her office at a speed of 3 kmph and back from the office to her house at 6 kmph. What is the average speed?
Elementary MathematicsStatistics
- A5 kmph
- B4.5 kmph
- C4 kmph
- D3.5 kmph
Explanation
For equal distances at speeds 3 and 6 km/h, the average speed is the harmonic mean. This equals 2·3·6/(3 + 6) = 36/9 = 4 km/h. Using the arithmetic mean 4.5 is the classic error here, so the answer is option C.