Chance rolls a 1-6 number cube. What is the probabilty that he will roll a prime number

B

Step-by-step explanation:

There are six numbers altogether. 2 3 and 5 are prime. One is odd, but it is not considered prime.

So P(prime) = 3/6 = 1/2

As a percent, this is 1/2 * 100 = 50%

85.560%

step-by-step explanation:

conditional probability is defined as:

p(a|b) = p(a∩b) / p(b)

in other words, the probability that a occurs, given that b has occurred = the probability that both a and b occur / the probability that b occurs.

in this example:

p(turns 64 | turns 44) = p(turns 64 & turns 44) / p(turns 44).

if someone turns 64, they must have already turned 44, so:

p(turns 64 | turns 44) = p(turns 64) / p(turns 44)

on page 42, we see that of the original 100,000, 94944 turn 44, and 81234 turn 64.   therefore:

p(turns 64 | turns 44) = 81234 / 94944

p(turns 64 | turns 44) = 0.85560