Question

Select the correct answer from each drop-down menu. A scientist is observing a sample of a radioactive substance. The table below shows the amount of the radioactive substance remaining, in milligrams, with respect to time, in hours, since the scientist began observing the sample.
Time (hours) 1 2 3 4 5
Amount Remaining (milligrams) 288 144 72 36 18
The independent variable in the relationship is the(time or amount remaining)and should be placed on the(x or y ). The dependent variable in the relationship is the(time or amount remaining)and should be placed on the(x or y ).

Answer 1

This is the 1/2 life formula. At time 0, the sample starts out 288 mg. That's the peek amount as far as he is concerned. It doesn't matter how that 288 mg got there. It only matters that that is his starting point. An hour later, he has 144 mg left. 2 hours later the number dropped to 72 and so on down.

So here are your answers

• Independent Variable: Time
• Axis: X
• The dependent variable: amount of substance remaining.
• Axis y.

If you are curious

Formula: P = A(1/2)^(x) where x starts at 0.