Two solutions are made. One has 10.0 g of glucose, of molar mass 180 g/mol, in 100 g of water…

Step 1. Glucose. $\dfrac{10.0}{180} = 0.0556\ \text{mol}$ in $0.100\ \text{kg}$, so $m = 0.556\ \text{mol/kg}$ and $\Delta T_f = 1.86\ \text{K kg/mol} \times 0.556\ \text{mol/kg} = 1.03\ \text{K}$.

Step 2. Sucrose. $\dfrac{10.0}{342} = 0.0292\ \text{mol}$ in $0.100\ \text{kg}$, so $m = 0.292\ \text{mol/kg}$ and $\Delta T_f = 1.86\ \text{K kg/mol} \times 0.292\ \text{mol/kg} = 0.544\ \text{K}$.

Step 3. Compare. The glucose solution has the larger fall, so it freezes at the lower temperature.