Given $\frac{a}{b}=\frac{1}{3}$ $\frac{b}{c}={2}$ $\frac{c}{d}=\frac{1}{2}$
$\frac{d}{e}=3$ $\frac{e}{f}=\frac{1}{4}$
b=3a=2c=d => d=3a
b=2c=d=3e => e = $\frac{b}{3}$
c = $\frac{d}{2} = \frac{3e}{2} = \frac{3f}{8}$
$\frac{a}{d} *\frac{b}{e} * \frac{c}{f}$ = $\frac{a}{3a} *\frac{b}{\frac{b}{3}} * \frac{c}{\frac{8c}{3}}$
=$\frac{3}{8}$