Example 5.61 from Prealgebra, 5.6 Ratios and Rate

Ratios and Rate: example 5.61

Hector's total cholesterol is $249$ mg/dl and his HDL cholesterol is $39$ mg/dl. ⓐ Find the ratio of his total cholesterol to his HDL cholesterol. ⓑ Assuming that a ratio less than $5$ to $1$ is considered good, what would you suggest to Hector?

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Solution
ⓐ First, write the words that express the ratio. We want to know the ratio of Hector's total cholesterol to his HDL cholesterol.

Write as a fraction. $\frac{total cholesterol}{HDL cholesterol}$

Substitute the values. $\frac{249}{39}$

Simplify. $\frac{83}{13}$

ⓑ Is Hector's cholesterol ratio ok? If we divide $83$ by $13$ we obtain approximately $6.4,$ so $\frac{83}{13} \approx \frac{6.4}{1} .$ Hector's cholesterol ratio is high! Hector should either lower his total cholesterol or raise his HDL cholesterol.

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

Find the patient's ratio of total cholesterol to HDL cholesterol using the given information.

Total cholesterol is $185$ mg/dL and HDL cholesterol is $40$ mg/dL.

How did it go?

Write as a fraction.	$\frac{total cholesterol}{HDL cholesterol}$
Substitute the values.	$\frac{249}{39}$
Simplify.	$\frac{83}{13}$

Solution

Your turn

Solution

Your turn