Question

If $H$ is harmonic mean between $7$ and $8$, then $\frac{H}{2}$ $=$

• A. $\frac{112}{15}$
• B. $\frac{56}{15}$
• C. $\frac{28}{15}$
• D. $\frac{14}{15}$

Answer 1

The correct option is B $\frac{56}{15}$

Harmonic mean between $7$ and $8$, then we need to find $\frac{H}{2}$

Therefore, $H=\frac{2}{\frac{1}{a}+\frac{1}{b}}=\frac{2ab}{a+b}=\frac{2(7\times 8)}{7+8}=\frac{2\left(56\right)}{15}$

$\Rightarrow \frac{H}{2}=\frac{56}{15}$