Discussion
If we toss three coins, the possible outcomes of appearing two heads can be written as :
Answer: C
The outcomes are written as \({}^{3}C_{2}\).
Getting exactly two heads with three coins means choosing which 2 of the 3 coins show heads:
\[ {}^{3}C_{2} = \frac{3!}{2!\,1!} = 3 \]
The three outcomes are HHT, HTH and THH. \({}^{3}C_{3}\) counts three heads, \({}^{3}C_{0}\) no heads, and \({}^{3}C_{1}\) one head (which also equals 3 numerically, but it counts the choice of the single head, not the two heads the question asks about).
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