Question

James types 50 words per minute. He spends 20 minutes typing his homework. What is the domain of this situation.

A. {all numbers between and including 0 and 50
B. {all numbers between and including 0 and 20}
C.{all numbers between 0 and 50}
D. {all numbers between 0 and 20}

Answer 1

B. {All Numbers between and including 0 and 20}

Explanation:

This is a graph of: Words (along y-axis) against minutes (z-axis)

As shown in attached graph sketch; the slope of this graph is 50 words per minute.

So the domain of this graph is all numbers between and including 0 and 20.

Answer 2

I swear I just answered this one only a few minutes ago.

Basically, this question is kinda lame, because it leaves you guess what’s the input and what’s the output. My guess is that someone would create the function to answer the question, “How many words has Jim typed after x minutes?” which makes the number of minutes of typing the input and the number of words typed up to that point the output.

In that situation, your inputs span from 0 minutes (the moment he’s about to start typing) to 20 (when his 20 minutes are done) and would include everything in between.

If someone tried to create a function that asked the inverse question “How many minutes did it take Jim to type x words?” then no answer from your list of 4 would work for the situation, so that leads me back to thinking my initial interpretation is correct.

You answer is B, from 0 to 20 and including 0 and 20.

But I’m not crazy, right? I already answered this one a few minutes ago, right?