A fair coin is tossed twice. What is the probability of getting exactly **two heads**?
A$\dfrac{1}{4}$
B$\dfrac{1}{2}$
C$\dfrac{2}{3}$
D$\dfrac{3}{4}$
Answer & Solution
Correct answer: A. $\dfrac{1}{4}$
Each toss is independent with $P(H) = \tfrac{1}{2}$. Probability of both heads:
$P(H \text{ and } H) = \tfrac{1}{2} \cdot \tfrac{1}{2} = \tfrac{1}{4}$.
Sample space $\{HH, HT, TH, TT\}$ — only one outcome (HH) gives two heads.
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