You have 2 stock solutions with the following concentrations. Glucose: 1.9 g/L. NaCl: 698 mg/L.?

The volume of stock solution of glucose used is independent of that of the NaCl. Therefore, we calculate on the stock solution of glucose only.

Stock solution: C₁ = 1.9 g/L, V₁ = ? mL
Diluted solution: C₂ = 0.02 g/L, V₂ = 1 L = 1000 mL

C₁ V₁ = C₂ V₂
Volume of glucose stock solution needed, V₁ = V₂ × (C₂/C₁) = 1000 × (0.02/1.9) mL = 10.53 mL