Question

A 0.1 mm sample of human blood has approximately 6000 red blood cells. An adult typically has 5.0 L of blood. How many red blood cells are in an adult? (1 mL = 1 cc). Use "E" for scientific notation.

Answer 1

 3.0 × 10¹¹ RBC's    (or)      3E11 RBC's

Solution:

Step 1: Convert mm³ into L;

As,

                                            1 mm³  =  1.0 × 10⁻⁶ Liters

So,

                                         0.1 mm³  =  X  Liters

Solving for X,

                       X  =  (0.1 mm³ × 1.0 × 10⁻⁶ Liters) ÷ 1 mm³

                       X  =  1.0 × 10⁻⁷ Liters

Step 2: Calculate No. of RBC's in 5 Liter Blood:

As given

                        1.0 × 10⁻⁷ Liters Blood contains  =  6000 RBC's

So,

                         5.0 Liters of Blood will contain  =  X  RBC's

Solving for X,

                      X  =  (5.0 Liters × 6000 RBC's) ÷ 1.0 × 10⁻⁷ Liters

                      X  =  3.0 × 10¹¹ RBC's

Or,

                     X  =  3E11 RBC's