Ben is greeting customers at a music store. Of the first 20 people he sees enter the store, 9 are wearing jackets and 11 are not. What is the experimental probability that the next person to enter the store will be wearing a jacket? Enter your answer as a simplified fraction.

The experimental probability that the next person to enter the store will be wearing a jacket is 9/40. Correct?

Matt's house number is a two-digit number. Neither of the digits is 0 and the house number is even. What is the probability that Matt's house number is 18?
1/36 probability.

Philip rolls a number cube 12 times. Which is the best prediction for the number of times that he will roll a number that is odd and less than 5?
4 times.

To find the experimental probability that the next person to enter the store will be wearing a jacket, you need to divide the number of people wearing jackets by the total number of people observed. In this case, out of the first 20 people observed, 9 were wearing jackets. Therefore, the experimental probability is 9/20.

However, the question asks for the experimental probability for the next person to enter the store, so you would divide the number of people wearing jackets by the total number of people observed plus 1. Since there were 9 people wearing jackets out of 20, the probability for the next person to enter wearing a jacket would be 9/21.

For the second question, if Matt's house number is a two-digit even number and neither of the digits is 0, then there are a total of 45 possible house numbers (excluding 00 and odd numbers). Since we are looking for the number 18 specifically, which is one of those 45 possible numbers, the probability is 1/45.

Lastly, for the prediction of the number of times Philip will roll an odd number less than 5, we can calculate it based on the probability of rolling an odd number (1, 3, or 5) and a number less than 5 (1, 2, 3, or 4) on a standard number cube.

The probability of rolling an odd number is 3/6 or 1/2, and the probability of rolling a number less than 5 is 4/6 or 2/3.

To find the probability of both events occurring together, we multiply the probabilities: (1/2) * (2/3) = 1/3.

Since Philip rolls the number cube 12 times, the best prediction for the number of times he will roll an odd number less than 5 would be 12 * (1/3) = 4 times.

For the first question, yes, the experimental probability that the next person to enter the store will be wearing a jacket is 9/40. This is calculated by dividing the number of people wearing jackets (9) by the total number of people (20).

For the second question, if Matt's house number is a two-digit number where both digits are non-zero and the number is even, then there are a total of 36 possible house numbers (since there are 9 possible choices for the tens digit and 4 possible choices for the units digit). Since we are only interested in the specific number 18, the probability that Matt's house number is 18 is 1/36.

For the third question, if Philip rolls a number cube 12 times, the best prediction for the number of times he will roll a number that is odd and less than 5 is 4 times. This is because there are 3 odd numbers less than 5 (1, 3, and 5) and rolling a number cube 12 times would statistically give an average of 4 occurrences.

done, check further up in the listing for your later post