If three unbiased coins are tossed simultaneously, then the probability of exactly two heads is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → \(\frac{3}{8}\)
Each coin can fall in 2 ways, so three coins give \(2\times2\times2=8\) equally likely outcomes. The probability is the number of favourable outcomes divided by 8.
All outcomes: HHH, HHT, HTH, THH, HTT, THT, TTH, TTT
Exactly two heads: HHT, HTH, THH, that is, 3 outcomes
Probability \(\displaystyle =\frac{3}{8}\)
Tip: “Exactly two” leaves out HHH. Counting “at least two heads” would give 4 outcomes and \(\frac{4}{8}=\frac{1}{2}\), which is Option (2).