Answer: The data are not arranged in a useful pattern. I arranged them as best I could and made a graph in Excel for demonstration.
Explanation: The data are plotted with mass on the x axis and volume on the y. Add a key to identify the top line as CU and the bottom as Al.
The density of Cu is 8.9 g/ml and 2.70 for Al.
The mass of copper increases by 17.8 grams going from 6 to 8 ml. (8.9 g/ml)*(2 ml) = 17.8 grams.
Copper is more dense. c The graph shows that for the same volumes, copper has the higher mass.