Using 3 of the same 100 sided die that david185000 used in his a "Probability Teaser" thread.
What would be the chances of:
1 of the die landing on a prime number.
2 of the die landing on a prime number.
3 of the die landing on a prime number.
Printable View
Using 3 of the same 100 sided die that david185000 used in his a "Probability Teaser" thread.
What would be the chances of:
1 of the die landing on a prime number.
2 of the die landing on a prime number.
3 of the die landing on a prime number.
For those who dont know:
a prime number is a number that can only exactly be divided by 1 and itself. e.g.
The only divisors of 13 are 1 and 13, making 13 a prime number, while the number 24 has divisors 1, 2, 3, 4, 6, 8, 12, and 24.
First you need the number of Primes below 100.....
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97
That are 25 numbers out off 100, so to get a prime on one 100 sided has the probability of 0.25. (i.e. ProbPrime 0.25 / ProbNoPrime 0.75
Q1 roll 4 dice and have only 1 Prime.
ProbPrime*probNoPrime^3=0.10546875
Q2 roll 4 dive and have 2 with a prime
ProbPrime^2*probNoPrime^2=0.03515625
Q3 roll 4 dive and have 3 with a prime
ProbPrime^3*probNoPrime=0.01171875
And finally t oget 4 primes
ProbPrime^4=0.00390625
What is the shape of a die with 100 sides if it is required that each side have the same probability of being faceup?