Final answer:
The division of 150.1 g by 45.0 ml should be expressed with three significant figures, resulting in a density of 3.35 g/mL, to match the volume measurement's significant figures.
Step-by-step explanation:
When solving the equation (150.1 g)/(45.0 ml), the answer's significant figures are determined by the value with the least number of significant figures, which in this case is the volume measurement (45.0 ml) with three significant figures. Therefore, the result of the division should also have three significant figures. When the calculation is performed, the result is a density which should be expressed as 3.35 g/mL, rounding to three significant figures, matching the least number of significant figures from the original measurements.