Difference between revisions of "2021 Fall AMC 10B Problems/Problem 4"

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At noon on a certain day, Minneapolis is <math>N</math> degrees warmer than St. Louis. At <math>4{:}00</math> the temperature in Minneapolis has fallen by <math>5</math> degrees while the temperature in St. Louis has risen by <math>3</math> degrees, at which time the temperatures in the two cities differ by <math>2</math> degrees. What is the product of all possible values of <math>N?</math>
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#REDIRECT [[2021_Fall_AMC_12B_Problems/Problem_3]]
 
 
<math>(\textbf{A})\: 10\qquad(\textbf{B}) \: 30\qquad(\textbf{C}) \: 60\qquad(\textbf{D}) \: 100\qquad(\textbf{E}) \: 120</math>
 
 
 
==Solution==
 
 
 
Let the temperature of Minneapolis at noon be <math>M</math> and let the temperature of St. Louis at noon be <math>S</math>. Then <math>M = N + S</math> and <math>(M-5)-(S+3) = |2| \implies M-S-8 = |2|</math>.
 
 
 
Substituting <math>M</math> into the second equation we have <math>N - 8 = |2| \implies N = 10, 6</math>.
 
 
 
The product of all possible values of N is therefore <math>10\cdot6=60=\boxed{C}</math>
 
 
 
~KingRavi
 

Latest revision as of 17:46, 3 January 2022