Marissa is reading over her blood work results from her doctor. According to the report, there are about 3.7 × 10^5 platelets and about 9,300 white blood cells in a microliter of blood.

Question

What is the total number of platelets and white blood cells in a microliter of blood?
A.
4.63 × 10^4
B.
3.8 × 10^4
C.
4.63 × 10^5
D.
3.8 × 10^5

Answer 1

To find the total number of platelets and white blood cells in a microliter of blood, we need to add the given quantities:

• Platelets: \(3.7 \times 10^5\)
• White blood cells: \(9,300\) (which can be expressed as \(9.3 \times 10^3\))

Now, we can add these two numbers. To do so, we need to express \(9.3 \times 10^3\) in terms of \(10^5\):

\[ 9.3 \times 10^3 = 0.093 \times 10^5 \]

Now, we can add the two quantities:

\[ 3.7 \times 10^5 + 0.093 \times 10^5 = (3.7 + 0.093) \times 10^5 = 3.793 \times 10^5 \]

Now, we can round \(3.793\) appropriately to significant figures based on the options given in the question:

The closest representation of \(3.793 \times 10^5\) to the options provided is \(3.8 \times 10^5\).

Thus, the total number of platelets and white blood cells in a microliter of blood is:

D. \(3.8 \times 10^5\)