Did you know that an unopened 355 mL can of diet Dr. Pepper will float in a lake? That's a fact! However, it's also a fact that an unopened 355mL can of regular Dr. Pepper will sink in that same lake! Based on these two facts, which type of soda is the least dense? Explain your answer.

An unopened can of Diet Dr. Pepper is the least dense.

Step-by-step explanation:

For a solid object to float in a liquid, it must be less dense.

Let's associate the density of Diet Dr. Pepper with x, Dr. Pepper with y, and lake water with z.

Because of the above fact, x < z, and y > z.  Thus, x < z < y, and x < y.

Hope it helps :) and let me know if you want me to elaborate.