Answer:
<u>A) Matched pairs design</u>
<u>Step-by-step explanation:</u>
In<em> </em><em>experimental design</em>, the match pairs experimental design is one that often involves only two treatment conditions; which in this case are the 'refrigerated and the room temperature battery storage types'.
Thus, these two treatment conditions form a matched pair because we are told that 10 fully charged batteries are placed into each type of storage.
They are essentially asking us to solve:

Solving this equation for x tells us that it will take around 80.1 years for the materials in the vault to reduce to 357 pounds.
Answer: it’s either 5x^3 -4x^2-7x or
-3x^3-4x^2-7x
Step-by-step explanation:
i put it in my calculator