Multiple choice

A person goes to a certain place at the speed of 4kmph. He returns on bicycle at the speed of 16 kmph. Find his average speed during the whole journey

  1. 3.63

  2. 9.6

  3. 6.4

  4. 6.3

  5. 4.5
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Average speed = 2 * v1 * v2 / (v1 + v2) = 2 * 4 * 16 / (4 + 16) = 128 / 20 = 6.4 kmph.

AI explanation

When equal distances are traveled at two different speeds, the average speed is found using the harmonic mean formula: 2xy divided by (x plus y). Substituting the speeds 4 kmph and 16 kmph gives 2 multiplied by 4 multiplied by 16, which equals 128. Dividing 128 by the sum of 4 and 16, which is 20, gives an average speed of 6.4 kmph.

Keep practicing — related questions