#8 - At Happywell Inc., last year the average annual salary

[Administrator]

Complete Question Explanation

Must Be True. The correct answer choice is (C).

Answer choice (A):

Answer choice (B):

Answer choice (C): This is the correct answer choice.

Answer choice (D):

Answer choice (E):

This explanation is still in progress. Please post any questions below!

[madisonzill]

Would you be able to explain this question? I guessed. I have trouble with number questions.

[KelseyWoods]

Hi Madison!

This is a Must Be True question which means we are using the facts in the stimulus to prove a fact in the answer choices. So our first step is to make sure we understand the facts.

Fact #1: Average salary for dieticians at Happywell last year was $50,000.
Fact #2: Average salary for physical therapists at Happywell last year was $42,000.
Fact #3: Average salary for all employees at Happywell last year was $40,000.

The important thing to remember about averages is that there are usually going to be some things above and below that average. If the average salary for dieticians is $50,000, that means that some dieticians earned more than $50,000 and some earned less than $50,000 (unless ALL dieticians earned exactly $50,000). If the average salary for physical therapists is $42,000, that means that some physical therapists earned more than $42,000 and some earned less than $42,000 (unless ALL physical therapists earned exactly $42,000). And if the average salary for ALL employees (which includes the dieticians and physical therapists) is $40,000, that means that some employees earned less than $40,000 because we already know that the dieticians and physical therapists earned more than $40,000.

If $40,000 is the average salary for employees, we know that at least one employee had to make less than $40,000, which means they made less than the average salary for physical therapists ($42,000). That proves answer choice (C): "At least one Happywell employee earned less than the average for a physical therapist last year."

For the other answer choices, we don't really know anything about the highest/lowest paid dieticians and physical therapists. As mentioned earlier, it's possible that all of the dieticians make exactly $50,000 and all of the physical therapists make exactly $42,000. It's also possible that half of the dieticians make $100,000 and half of them make $0 and half of the physical therapists make $84,000 and the other half make $0. We have no idea how many dieticians and physical therapists there are and we have no idea how much the highest and lowest paid dieticians and physical therapists get paid. So we can't prove answer choices (A), (B), (D), and (E).

Hope this helps!

Best,
Kelsey