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