A coin is thrown 3 times. What is the probability that&nb...
A coin is thrown 3 times. What is the probability that at least one head is obtained?
78
38
None the above
18
Correct answer is A
Sample space = {HHH, HHT, HTH, THH, TTH, THT, HTT, TTT}
Total number of possible outcomes = 2 x 2 x 2 = 8
favourable number of outcomes = 7
∴Pr(at least one head) = 78