Answer
$$54 \space g \space of \space Acetic \space acid$$
Work Step by Step
$$1.006 \space g/mL \times \frac{5.4 \space g_{Acetic \space Acid}}{100 \space g} \approx 0.054 \space g_{Acetic \space Acid}/mL$$
$1.00 \space L = 1000 \space mL$
$$0.054 \space g_{Acetic \space Acid}/mL \times 1000 \space mL = 54 \space g_{Acetic \space Acid}$$
