It takes Bobby and Jeremy 15 minutes to set up 5 tables. If Bobby and Jeremy work at a constant rate, which best describes a possible constant of proportionality?
Okay, so y = kx where k is the constant of proportionality. Just plug in the values...the time affects the number of tables, so it must be the independent variable, or x value.
5 = 15k
Divide both sides by 15, and you are left with 1/3. This is the constant of proportionality.
