Three unbiased coins are tossed. What is the probability of getting at least 2 heads?

Answer: Option B

Here S = {TTT, TTH, THT, HTT, THH, HTH, HHT, HHH}
Let E = event of getting at least two heads = {THH, HTH, HHT, HHH}
$$\therefore P(E)=\frac{n(E)}{n(S)}=\frac{4}{8}=\frac{1}{2}$$