Question

f(-15)=0.6, means if mamadou runs down 15 stairs, he will burn 15 calories. this interpretation makes sense in the context of the problem. mamadou runs up 50 stairs, he will burn 6 calories. this interpretation does not make sense makes sense in the context of the problem. f(22.5)=2.7, means if mamadou runs up 22.5 stairs, he will burn 2.7 calories. this interpretation makes sense in the context of the problem. based on the observations above, it is clear that an appropriate domain for the function is all real numbers

Explanation:

Step1: Analyze $f(-15) = 0.6$

Running down 15 stairs burning 15 calories is wrong as given $f(-15)=0.6$. So this interpretation does NOT make sense.

Step2: Analyze $f(50)$

If running up 50 stairs burns 6 calories, we need to check if it aligns with the function. But no information about the function relationship is given clearly to support this, so this interpretation does NOT make sense.

Step3: Analyze $f(22.5)=2.7$

Running up 22.5 stairs burning 2.7 calories may or may not be correct depending on the function. But since we have non - integer number of stairs, in real - life context, number of stairs is usually a whole number, so this interpretation does NOT make sense.

Step4: Analyze domain

Since number of stairs in real - life is non - negative integer (you can't have a negative or non - whole number of stairs in a practical sense), the domain should not be all real numbers. The domain should be non - negative integers.

Answer:

1. $f(-15) = 0.6$: does NOT make sense
2. $f(50)=6$: does NOT make sense
3. $f(22.5)=2.7$: does NOT make sense
4. Domain: non - negative integers