Harmonic mean of a series is the reciprocal of the arithmetic mean of the reciprocal of the values of its items.
Calculation of Harmonic Mean (H.M.) :
Harmonic Mean is used in the following cases :-
- For determining average speed or velocity.
- To find out average price.
- If the item given in the question which is variable is to be kept as constant in the answer, or vice versa, then harmonic mean will be calculated.