Five fair coins are tossed together. What is the probability of getting at least four heads?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → \(\frac{3}{16}\)
Five coins give \(2^5\) equally likely outcomes. “At least four heads” means exactly four heads or exactly five heads, and these two cases are added.
Total outcomes \(=2^5=32\)
Exactly four heads: choose the one coin showing tails, \({}^{5}C_1=5\) ways
Exactly five heads: HHHHH, 1 way
Favourable outcomes \(=5+1=6\)
Probability \(\displaystyle =\frac{6}{32}=\frac{3}{16}\)