Here is the answer of the question…

To determine how much water must be added to a 100cc solution of 80% boric acid to reduce it to a 50% solution, you can use the following formula:

(C1)(V1) = (C2)(V2)

Where:

- C1 is the concentration of the initial solution (80% or 0.80 as a decimal).
- V1 is the volume of the initial solution (100cc).
- C2 is the concentration of the final solution (50% or 0.50 as a decimal).
- V2 is the volume of the water to be added (which we want to find).

Let’s plug in the values and solve for V2:

(0.80)(100cc) = (0.50)(100cc + V2)

Now, let’s solve for V2:

80cc = 50cc + 0.50V2

Subtract 50cc from both sides:

30cc = 0.50V2

Now, divide both sides by 0.50 to isolate V2:

V2 = 30cc / 0.50

V2 = 60cc

So, you need to add 60cc of water to the 100cc of the 80% boric acid solution to reduce it to a 50% solution.