Please help! How many ml of sterile water must be added to 75 ml sucrose to make a 2.5% solution?

Question

How many ml of sterile water must be added to 75 ml of sucrose to make a 2.5% solution?

Answer 1

Let w mL be the amount of pure water to be added to pure sucrose to make the 2.5% solution of sucrose.

When the sucrose is diluted, we have 75mL of sucrose in w+75 mL of solution, that is: 75/(w+75)=2.5%=1/40.

Therefore, cross-multiplying, w+75=40×75=3000mL, w=3000-75=2925mL or 2.925L.

So 2925mL of pure water are required to make 3L of 2.5% sucrose solution.