2022 AMC 8 Problem 9
Attempt Problem 9 of the 2022 AMC 8 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2022 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
9.
A cup of boiling water ( F) is placed to cool in a room whose temperature remains constant at F. Suppose the difference between the water temperature and the room temperature is halved every minutes. What is the water temperature, in degrees Fahrenheit, after minutes?
Answer: B
Small hint:
Track the difference from room temperature
Big hint:
In minutes, the difference is halved times
Solution:
The current difference is
Since we have minutes while halving every minutes, we halve the difference times.
This means the difference is multiplied by so our new difference is This makes our final temperature
Thus, the correct answer is B.
Problem 9 in other years
- 1985 AMC 8
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