# math

posted by
**hi**
.

pls. explain how to get this:

A number x is the harmonic mean of two

numbers a and b if 1/x

is the mean of 1/a

and 1/b.

a) Write an equation to represent the harmonic

mean of a and b.

b) Determine the harmonic mean of 12 and 15.

c) The harmonic mean of 6 and another

number is 1.2. Determine the other number.

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