Molar mass of sugar (C12H22O11) = (12×12)+(1×22)+(11×16) = 342 g mol-1
No. of moles in 20g of sugar = 20/342 = 0.0585 mole
Volume of Solution = 2L (given)
Molar concentration = Moles of solute/Volume of solution in L = 0.0585mol/2L = 0.0293 mol L-1 = 0.0293 M