Question

How many ways can a person toss a coin 15 times so that the number of heads is between 8 and 12 inclusive

Answer 1

16263 ways

Explanation:

Given that:

Number of coin tosses, n = 15

Number of heads is between 8 and 12 inclusive

For 8 heads, tails = 15 - 8 = 7

15! / (8!7!) = 6435

For 9 heads, tails = 15 - 9 = 6

15! / (9!6!) = 5005

For 10 heads, tails = 15 - 10 = 5

15! / (10!5!) = 3003

For 11 heads, tails = 15 - 11 = 4

15! / (11!4!) = 1365

For 12 heads, tails = 15 - 8 = 3

15! / (12!3!) = 455

(6435 + 5005 + 3003 + 1365 + 455) = 16,263 ways