Question

a human body contains approximately 5 liters of blood, 40% of which is red blood ce
blood carries oxygen and nutrients to living cells and takes away their waste products.
also delivers immune cells to fight infections and contains platelets that can form a

• hematocrit level:

the percentage of
red blood cells in a
blood sample.

• 5 l of blood has a

hematocrit level
of 40%
the volume of a single
red blood cell
is approximately
9 × 10⁻¹⁴ liters
approximately how many
red blood cells are in a
typical adult human body?
× 10

Explanation:

Step1: Calculate the volume of red blood cells

The total blood volume is \(5L\), and the hematocrit level (percentage of red - blood cells) is \(40\%\). So the volume of red blood cells \(V = 5\times0.4=2L\)

Step2: Calculate the number of red blood cells

The volume of a single red - blood cell \(v = 9\times10^{-14}L\). Let the number of red - blood cells be \(n\). Using the formula \(n=\frac{V}{v}\), we substitute \(V = 2\) and \(v=9\times 10^{-14}\)

$$ n=\frac{2}{9\times 10^{-14}}=\frac{2}{9}\times10^{14}\approx0.22\times10^{14} = 2.2\times10^{13} $$

Answer:

\(2.2\times10^{13}\)