MathDB

An unfair coin lands on heads with a probability of

\tfrac{1}{4}

. When tossed

n

times, the probability of exactly two heads is the same as the probability of exactly three heads. What is the value of

n

\textbf {(A) } 5 \qquad \textbf {(B) } 8 \qquad \textbf {(C) } 10 \qquad \textbf {(D) } 11 \qquad \textbf {(E) } 13

Problem Statement