2021 AMC 12B Fall Problem 3
Attempt Problem 3 of the 2021 AMC 12B Fall 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 2021 AMC 12B Fall solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
3.
At noon on a certain day, Minneapolis is degrees warmer than St. Louis. At the temperature in Minneapolis has fallen by degrees while the temperature in St. Louis has risen by degrees, at which time the temperatures in the two cities differ by degrees. What is the product of all possible values of
Answer: C
Small hint:
At noon the difference is ; track how each change affects the gap
Big hint:
The new difference is
Solution:
At noon the gap is Minneapolis then loses degrees and St. Louis gains so the gap changes by The new absolute difference is
This gives or whose product is
Thus, the correct answer is C.
Problem 3 in other years
- 1950 AMC 12
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