Answer: The mass of sample is 21.6 grams.
Step-by-step explanation:
We are given:
Volume of cylinder without object,
= 10 mL
Volume of cylinder with object,
= 18 mL
Volume of object =

To calculate volume of a substance, we use the equation:

We are given:
Density of sample (aluminum) = 2.7 g/mL
Volume of sample (aluminum) = 8 mL
Putting values in above equation, we get:

Hence, the mass of sample is 21.6 grams.