When six fair coins are tossed simultaneously, in how many of the outcomes will at most three of the coins turn up as heads?
A
25
B
41
C
22
D
42
E
31
Correct Answer: 42
The question requires you to find number of the outcomes in which at most 3 coins turn up as heads.i.e., 0 coins turn heads or 1 coin turns head or 2 coins turn heads or 3 coins turn heads.The number of outcomes in which 0 coins turn heads is, 6C0 = 1 outcome.The number of outcomes in which 1 coin turns head is, 6C1 = 6 outcomes.The number of outcomes in which 2 coins turn heads is, 6C2 = 15 outcomes.The number of outcomes in which 3 coins turn heads is, 6C3 = 20 outcomes.Therefore, total number of outcomes= 1 + 6 + 15 + 20
= 42 outcomes.