Daniel W. answered • 05/21/20
College-level English, Science, and Math skills
This problem is asking us about simple probability.
All the different problems can be found using the same solution… x/n where x is the number of students for that category, and n is the total number of students. In this problem, n is always 30 because there are 30 students in class.
So… for the first problem… The number of students who have a birthday in March (x) is 3. The total number of students is 30.
So… the probability that a random student picked has a birthday in March is 3/30… or 1/10.
For the second problem… we use the same exact strategy, but the numbers have changed. The number of students who have a birthday in October (x) is 1. The total number of students is 30.
So… the probability that a random student picked has a birthday in October is 1/30.
For the third problem… we have to use a different strategy, but it is just as easy. Now, we add together the students who have birthdays in June, July, or August. The number of students who have a birthday in June, July, or August (x) is 8. The total number of students is 30.
So… the probability that a random student picked has a birthday in June, July, or August is 8/30… or 4/15.
For the last problem… we have to use a different strategy again, but it is just as easy as the last three. Now, we add together all the student’s birthdays except December. The number of students who do not have a birthday in December (x) is 28. The total number of students is 30.
So… the probability that a random student picked has a birthday not in December is 28/30... or 14/15.
