Molality of a solution is 1m. If the density of the solution is 0.8g/cc, the molarity of the solution will be (molar mass of solute = 80g)

Molality of the solution = 1m
Number moles of solute = 1
Weight of solute =  1 x 80g = 80g
Weight of solvent = 1000g
Weight solution =   ${\mathrm{W}}_{\mathrm{solvent}}+{\mathrm{W}}_{\mathrm{solute}}$
                                 =  (1000+80)g
Volume of solution = $\frac{{\mathrm{w}}_{\mathrm{solution}}}{{\mathrm{d}}_{\mathrm{solution}}}$

 Volume of solution   = $\frac{1080}{0.8}\mathrm{cc}$

                                         $\begin{array}{l}\mathrm{M}={\mathrm{n}}_{\mathrm{solute}}\times \frac{1000}{{\mathrm{V}}_{\mathrm{solution}}}\\ =1\times \frac{1000}{\left(\frac{1080}{0.8}\right)}\\ =1\times \frac{800}{1080}\\ =0.74\mathrm{M}\end{array}$