Difference between revisions of "2020 AMC 10B Problems/Problem 11"
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<math>\frac{10\cdot10}{252}=\boxed{\textbf{(D) }\frac{25}{63}}</math> ~quacker88 | <math>\frac{10\cdot10}{252}=\boxed{\textbf{(D) }\frac{25}{63}}</math> ~quacker88 | ||
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+ | ==Video Solution== | ||
+ | https://youtu.be/t6yjfKXpwDs | ||
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+ | ~IceMatrix | ||
==See Also== | ==See Also== | ||
{{AMC10 box|year=2020|ab=B|num-b=10|num-a=12}} | {{AMC10 box|year=2020|ab=B|num-b=10|num-a=12}} | ||
{{MAA Notice}} | {{MAA Notice}} |
Revision as of 18:33, 7 February 2020
Contents
Problem
Ms. Carr asks her students to read any 5 of the 10 books on a reading list. Harold randomly selects 5 books from this list, and Betty does the same. What is the probability that there are exactly 2 books that they both select?
Solution
We don't care about which books Harold selects. We just care that Betty picks books from Harold's list and
that aren't on Harold's list.
The total amount of combinations of books that Betty can select is .
There are ways for Betty to choose
of the books that are on Harold's list.
From the remaining books that aren't on Harold's list, there are
ways to choose
of them.
~quacker88
Video Solution
~IceMatrix
See Also
2020 AMC 10B (Problems • Answer Key • Resources) | ||
Preceded by Problem 10 |
Followed by Problem 12 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | ||
All AMC 10 Problems and Solutions |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.