A solution is prepared by dissolving W grams of a non-electrolyte...

For isotonic solutions at the same temperature, their osmotic pressures are equal. Since both the polymer and glucose are non-electrolytes, their van 't Hoff factors are $i=1$, which implies their molar concentrations must be equal.

Molar mass of glucose ($\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6$) $= 6 \times 12 + 12 \times 1 + 6 \times 16 = 180 \text{ g mol}^{-1}$

Concentration of glucose solution, $C_2 = \dfrac{0.18}{180} \times \dfrac{1000}{100} = 0.01 \text{ mol L}^{-1}$

Concentration of polymer solution, $C_1 = \dfrac{W}{6000} \times \dfrac{1000}{500} = \dfrac{W}{3000} \text{ mol L}^{-1}$

Equating the concentrations $C_1 = C_2$:

$\dfrac{W}{3000} = 0.01$

$W = 30 \text{ g}$

Answer: $30 \text{ g}$