Find the Harmonic Mean (H.M.) between 4 and 6.
Answer: B
The Harmonic Mean of two numbers a and b is given by the formula \(H.M. = \frac{2ab}{a+b}\). Here, a=4 and b=6. \(H.M. = \frac{2 \times 4 \times 6}{4+6} = \frac{48}{10} = 4.8\).