Three unbiased coins are tossed together. What is the probability of getting at least one head?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → \(\frac{7}{8}\)
“At least one head” fails only when no head at all appears, so its probability is \(1-\) P(no head).
Outcomes with three coins \(=2\times2\times2=8\)
No head means TTT: 1 outcome, so P(no head) \(\displaystyle =\frac{1}{8}\)
P(at least one head) \(\displaystyle =1-\frac{1}{8}=\frac{7}{8}\)