a,b,c are said to be in Harmonic Progression if their reciprocals $\dfrac{1}{a},\dfrac{1}{b},\dfrac{1}{c}$ are in Arithmetic progression. What would be the value of x for which 3, x, 6 are in Harmonic Progression.
4 1/2
4
5
5 1/2
Explanation:
If a,b,c are in Harmonic,
b is harmonic between a and c.
b=$\dfrac{2ac}{a+c}$
=$\dfrac{2\times3\times6}{9}$
= 4