Question

a 4 ml tube of blood contains 7.2 mg of cholesterol, what is the mg% of cholesterol (i.e., how many mg of cholesterol are in 100 ml of blood)?

Explanation:

Step1: Find mg per mL

First, find how many mg of cholesterol are in 1 mL of blood. We know 4 mL has 7.2 mg, so per mL it's $\frac{7.2}{4}$ mg/mL.
$\frac{7.2}{4} = 1.8$ mg/mL

Step2: Calculate for 100 mL

Now, to find the amount in 100 mL, multiply the mg per mL by 100. So, $1.8 \times 100$ mg.
$1.8 \times 100 = 180$ mg

Answer:

180 (corresponding to the option "180")