Chapter 5, Problem 16CR

To determine

To give the letter of the correct answer to find the solution in (ml) of an 8% saline should be added to 600ml of a 3% solution to produce a 5% solution.

Answer to Problem 16CR

The correct answer is c.

Explanation of Solution

Given that: The solution in (ml) of an 8% saline should be added to 600ml of a 3% solution to produce a 5% solution.

Formula:

  $\text{Solution(ml)= volume(ml) ×rate\%}$

Let total solution in (ml) of 8% be x

  $\Rightarrow x\times 8\%=x\times \frac{8}{100}=0.08x$

Now, add 600 ml of a 3% in the solution

  $\begin{array}{l}0.08x+600(ml)\times \frac{3}{100}\\ 0.08x+\mathrm{18.........}(i)\end{array}$

For production of 5% solution add in the 600 ml

  $\frac{5}{100}(x+600)=0.05(x+600)\mathrm{...........}(ii)$

Compare equation (i) and (ii)

  $\begin{array}{c}0.08x+18(ml)=0.05(x+600(ml))\\ 0.08x+18(ml)=0.05x+30(ml)\\ 0.03x=12(ml)\\ x=\frac{12}{0.03}(ml)=400ml\end{array}$

Hence, the correct option is c.