The density of the given solution is 1.110g mL^-1.

Since the solute is NaOH, the molar mass is 40. Since the solution is 3 molal, it means 3 moles of NaOH is dissolved in 1000g of water, or 120g of NaOH in 1000g of water. The total mass of the solution should therefore be 1120g. Since the mass and density is given, the volume is calculated by

1.110 = 1120/Volume

Volume = 1009mL = 1.009L

Molarity of the solution can now be calculated

M = 3 moles/1.009L = 2.97M.