#### Answer

$\frac{1}{9}$

#### Work Step by Step

We can write the given ratio as a fraction and then simplify in lowest terms.
Since 1 day has 24 hours, we can write 3 days as $(3\times24)=72$ hours.
$\frac{8hours}{72hours}$
Since both the denominator and numerator have the same unit, we can divide out the common unit.
$\frac{8}{72}=\frac{8\div8}{72\div8}=\frac{1}{9}$