Hey Sara! Here we are looking for density of the solid.
density solid = mass/volume
density of solid = grams/mL
What we know is how many grams of solid we have, all we need to find out is how many mL of solid we have. To do that we will first need to find out how many mL of benzene was added. And we can do that easily because be know the total volume in mL of the contents of the cylinder, and we have the density of benzene and the total grams of both the solid and benzene together.
58.80 g - 25 g = 33.80 g of benzene.
33.80 g benzene x ( 1mL/ 0.880 g benzene) = 38.41 mL of benzene.
50mL total - 38.41 mL benzene = 11.59 mL solid.
Now we have everything we need to find the density of the solid.
density of solid = 25 grams / 11.59 mL
density of solid = 2.15 g/mL
Hope you find this helpful!