GATE | GATE-CS-2002 | Question 41

Four fair coins are tossed simultaneously. The probability that at least one head and one tail turn up is :
(A) 1/16
(B) 1/8
(C) 7/8
(D) 15/16

Answer: (C)
Explanation: There are only two cases (when all head or all tail) against the given output. So the required probability is (16-2)/16 = 7/8.
Quiz of this Question