Answer
$\frac{7}{8} \cdot \frac{16}{21} \cdot \frac{1}{2} = \frac{1}{3}$.
Work Step by Step
$\frac{7}{8} \cdot \frac{16}{21} \cdot \frac{1}{2} = \frac{1}{8} \cdot \frac{16}{3} \cdot \frac{1}{2} = \frac{1}{1} \cdot \frac{2}{3} \cdot \frac{1}{2} = \frac{1}{1} \cdot \frac{1}{3} \cdot \frac{1}{1} = \frac{1 \cdot 1 \cdot 1}{1 \cdot 3 \cdot 1} = \frac{1}{3}$.