To solve the problem of determining how many pounds of a patient's body weight is blood when blood accounts for 7% of the total body weight, we follow these steps:
1. Identify the total body weight: The patient weighs 176 pounds.
2. Determine the percentage of the body weight that is blood: Blood accounts for 7% of the total body weight.
3. Convert the percentage to a decimal for calculation purposes: 7% is equivalent to 0.07.
4. Calculate the weight of the blood: Multiply the total body weight by the decimal form of the percentage to find the weight of blood.
[tex]\[
\text{Weight of blood} = 176 \, \text{pounds} \times 0.07
\][/tex]
5. Perform the multiplication:
[tex]\[
176 \times 0.07 = 12.32
\][/tex]
6. Round the result to the nearest tenth: When rounding 12.32 to the nearest tenth, we get 12.3.
7. Select the correct answer from the provided options: The correct rounded value, 12.3 lbs, corresponds to answer choice b.
Thus, when rounded to the nearest tenth, the number of pounds of the patient's body weight attributed to blood is 12.3 pounds. Therefore, the correct answer is:
b. O 12.3 lb
