MathDB

13

Part of 2022 MIG

Problems(2)

2022 A Individual #13

Source:

4/28/2022
Consider the numbers 11 through 66 numbered on the coins below. Ella takes a coin from each of the three columns. Bella takes a coin from each of the remaining two columns. Cassandra takes the remaining coin. In how many ways could they have taken out the six coins?
[asy] size(100); draw(Circle((0,0),0.45)); label("11",(0,0)); draw(Circle((0,1),0.45)); label("22",(0,1)); draw(Circle((0,2),0.45)); label("33",(0,2)); draw(Circle((1,0),0.45)); label("55",(1,0)); draw(Circle((1,1),0.45)); label("44",(1,1)); draw(Circle((2,0),0.45)); label("66",(2,0)); [/asy] <spanclass=latexbold>(A)</span>9<spanclass=latexbold>(B)</span>12<spanclass=latexbold>(C)</span>15<spanclass=latexbold>(D)</span>18<spanclass=latexbold>(E)</span>20<span class='latex-bold'>(A) </span>9\qquad<span class='latex-bold'>(B) </span>12\qquad<span class='latex-bold'>(C) </span>15\qquad<span class='latex-bold'>(D) </span>18\qquad<span class='latex-bold'>(E) </span>20
2022 A Individual
2022 B Individual #13

Source:

4/30/2022
Sarah is leading a class of 3535 students. Initially, all students are standing. Each time Sarah waves her hands, a prime number of standing students sit down. If no one is left standing after Sarah waves her hands 33 times, what is the greatest possible number of students that could have been standing before her third wave? <spanclass=latexbold>(A)</span>23<spanclass=latexbold>(B)</span>27<spanclass=latexbold>(C)</span>29<spanclass=latexbold>(D)</span>31<spanclass=latexbold>(E)</span>33<span class='latex-bold'>(A) </span>23\qquad<span class='latex-bold'>(B) </span>27\qquad<span class='latex-bold'>(C) </span>29\qquad<span class='latex-bold'>(D) </span>31\qquad<span class='latex-bold'>(E) </span>33
2022 B Individual