A researcher is comparing the effectiveness of three devices designed to help people who snore. There are 120 people who snore participating in the experiment. Using a table of random digits, the researcher will randomly place the participants into three equally sized treatment groups suitable for comparison. How many unique random numbers need to be selected from the table of random digits?

3
40
80
120

40

Step-by-step explanation:

Divide 120 by 3

Meaning you are taking the total nuber by the nuber which is going to be divided

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.