Question

Three unbiased coins are tossed together, then which of the following is true?

• A. The probability of getting exactly 2 heads is $\frac{1}{2}$
• B. The probability of getting atleast one head is $\frac{5}{8}$
• C. The probability of getting at least 2 tails is $\frac{3}{8}$
• D. The probability of getting exactly one tail is $\frac{3}{8}$

Answer 1

The correct option is D

The probability of getting exactly one tail is $\frac{3}{8}$

Sample Space = {HHH, HHT, HTH, HTT, THH, THT, TTH, TTT}
(a) P(exactly 2 heads) $=\frac{3}{8}$
(b) P (atleast one head) $=\frac{7}{8}$
(c) P(at least 2 tails) $=\frac{4}{8}$ = $\frac{1}{2}$
(d) P(exactly one tail) $=\frac{3}{8}$