Question

Roll a 20-sided die 10 times. Find the probability of getting: i. At least one six ii. At least one five and one six iii. 3 sixes given that no number larger than 12 appears iv. 3 sixes, 2 twelves, 4 twos, and 1 eight v. 1 triple, 3 doubles, and 1 single

Answer 1

the probability of getting a 6 in a roll of 20 sided die is

i) If the die is rolled 10 times, the probability of getting At least one six =1- the probability of getting no six

ii) the probability of getting At least one five and one six =1- the probability of getting no six and no 5

iii) A = getting 3 sixes

B = no number larger than 12 appears

iv) Total number of ways to get 3 sixes, 2 twelves, 4 twos, and 1 eight =

probability of getting six, twelve,two, 1 is same for a toss: p=0.5

hence the required probability is