AMC 12C 2020 Problems

Revision as of 13:01, 21 April 2020 by Shiamk (talk | contribs) (Problem 4)

Problem 1

What is the sum of the solutions of the equation $(x + 4)(x - 5)(x + 6) = 0$?


$\textbf{(A)}\ -5 \qquad\textbf{(B)}\ 0 \qquad\textbf{(C)}\ 5 \qquad\textbf{(D)}\ 12 \qquad\textbf{(E)}\ 14$


Problem 2

What is the numerical value of the sum $\sum_{k = 1}^{11}(i^{3} + i^{2})$


$\textbf{(A)}\ 4000 \qquad\textbf{(B)}\ 4608 \qquad\textbf{(C)}\ 4862 \qquad\textbf{(D)}\ 5792 \qquad\textbf{(E)}\ 6100$


Problem 3

In a bag are $7$ marbles consisting of $3$ blue marbles and $4$ red marbles. If each marble is pulled out $1$ at a time, what is the probability that the $6th$ marble pulled out red?


$\textbf{(A)}\ 0 \qquad\textbf{(B)}\ \frac{1}{8} \qquad\textbf{(C)}\ \frac{1}{2} \qquad\textbf{(D)}\ \frac{4}{7} \qquad\textbf{(E)}\ 1$


Problem 4

A lamb is tied to a post at the origin $(0, 0)$ on the real $xy$ plane with a rope that measures $5$ units. $2$ wolves are tied with ropes of length $5$ as well, both of them being at points $(5, 5)$, and $(-5, -5)$. What is the area that the lamb can run around without being in the range of the wolves?