A solution is made by mixing 90.6 g of magnesium sulfate heptahydrate with 2320.0 g of water.

Question

690.00 mL of the solution has a mass of 745.20 g.
What is the molarity of the magnesium sulfate solution?

Answer 1

mols MgSO4.7H2O = 90.6g/molar mass MgSO4.7H2O

density solution = g/mL = (2320+90.6)/690 = about 1.08 but you should be more careful.
v = mass/density = (2320+90.6)/1.08 = ?mL and convert to L then
M = mols/L solution.

Answer 2

I made typos galore here. The density is g/mL =
density = mass/volume = 745.2g/690 mL = 1.08 g/mL and not the numbers I showed. The density of 1.08 g/mL; however, is correct. The rest of the problem looks ok to me.