Difference between revisions of "2018 AMC 10A Problems/Problem 3"
Ishankhare (talk | contribs) (Created page with "A unit of blood expires after <math>10!=10\cdot 9 \cdot 8 \cdots 1</math> seconds. Yasin donates a unit of blood at noon of January 1. On what day does his unit of blood expir...") |
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<math>\textbf{(A) }\text{January 2}\qquad\textbf{(B) }\text{January 12}\qquad\textbf{(C) }\text{January 22}\qquad\textbf{(D) }\text{Febuary 11}\qquad\textbf{(E) }\text{Febuary 12}</math> | <math>\textbf{(A) }\text{January 2}\qquad\textbf{(B) }\text{January 12}\qquad\textbf{(C) }\text{January 22}\qquad\textbf{(D) }\text{Febuary 11}\qquad\textbf{(E) }\text{Febuary 12}</math> | ||
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+ | <h2>Solution</h2> | ||
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+ | <math>10! = 10\cdot 9\cdot 8\cdot 7\cdot 6\cdot 5\cdot 4\cdot 3\cdot 2\cdot 1</math> | ||
+ | Convert <math>10!</math> seconds to minutes: <math>9\cdot 8\cdot 7\cdot 5\cdot 4\cdot 3\cdot 2</math> minutes | ||
+ | Convert minutes to hours: <math>9\cdot 8\cdot 7\cdot 2</math> hours. | ||
+ | Convert hours to days: <math>3\cdot 7\cdot 2 = 42</math> days. | ||
+ | |||
+ | <math>42</math> days after January 1 is <math>\fbox{\textbf{(E) }\text{Febuary 12}}</math> |
Revision as of 14:24, 8 February 2018
A unit of blood expires after seconds. Yasin donates a unit of blood at noon of January 1. On what day does his unit of blood expire?
Solution
Convert
seconds to minutes:
minutes
Convert minutes to hours:
hours.
Convert hours to days:
days.
days after January 1 is