8 coins are tossed. Whats is the probability that one and only one turns up head ?
Choose the correct choice:
A) 1/256	B) 1/32	C) 1/64	D) 1/128	E) 1/189
Explanation :   Possible outcomes(Sample space) when 8 coins are tossed are: (H, H, H, H, H, H, H, H), (H, H, H, H, H, H, H, T), (H, H, H, H, H, H, T, H), (H, H, H, H, H, H, T, T), ....... (T, T, T, T, T, T, T, T) = 28   Required outcomes: (H, T, T, T, T, T, T, T), (T, H, T, T, T, T, T, T), (T, T, H, T, T, T, T, T), (T, T, T, H, T, T, T, T), (T, T, T, T, H, T, T, T), (T, T, T, T, T, H, T, T), (T, T, T, T, T, T, H, T), (T, T, T, T, T, T, T, H) = 8   So the required probability = 8/28 = 1/32   Answer : 1/32
<result>B</result>
8 coins are tossed. Whats is the probability that one and only one turns up head ?