Chapter 8.1, Problem 18P

To determine

To find the number of red blood cell to be found in $\text{6 mL}$ of diluted solution.

Answer to Problem 18P

The number of red blood cells is $1.5\times {10}^5$ .

Explanation of Solution

Given information:

The given statement is:

“The average number of red blood cells in a milliliter (mL) of human blood is $5\times {10}^6$ . For a certain test, a laboratory technician diluted one part of a blood sample with $199$ parts of salt water. How many red cells would the technician expect to find in $\text{6 mL}$ of the diluted solution?”

Calculation :

The quantity in mL of the red blood cells can be calculated by:

  $\begin{array}{l}\frac{y_1}{x_1{}^2}=\frac{y_2}{x_2{}^2}\\ \frac{1}{199}=\frac{y_2}{6}\\ y_2=\frac{1\times 6}{199}\\ y_2=0.03\end{array}$

The number of red blood cells in $\text{0}\text{.03 mL}$ of blood can be calculated by:

  $0.03\times 5\times {10}^6=1.5\times {10}^5$

Hence, the number of red blood cells is $1.5\times {10}^5$ .