spots is 5x4/2=10. The total number of outcomes in five

tosses is 2^5=36. Then, the probability of getting exactly two

heads in five tosses is equal to 10/36=5/18.

14) The number of possibilities to place three heads in six

spots is (6x5x4)/(2x3)=20. The total number of outcomes in

five tosses is 2^6=64. Then, the probability of getting exactly

three heads in six tosses is equal to 20/64=5/18.

15) The probability of getting exactly three heads in five

tosses (three heads and two tails) is the same as the

probability of getting exactly two heads in five tosses (three

tails and two heads) – 5/18.