)an instructor gives his class a set of 18 problems with the information that the next quiz will consist of a random selection of 9 of them. if a student has figured out how to do 13 of the problems, what is the probability the he or she will answer correctly

The probability the he or she will answer correctly is 1.5%

Step-by-step explanation:

In all, there are 18 problems. In this question, the order of which the problems are sorted for the quiz makes no difference. For example, if the question A of the quiz is P1 and question B P2, and question A P2 and question B P1, it is the same thing.

There are 18 problems and 9 are going to be selected. So, there is going to be a combination of 9 elements from a set of 18 elements.

A combination of n elements from a set of m objects has the following formula:

In this question, m = 18, n = 9. So the total number of possibilities is:

Now we have to calculate the number of desired outcomes. This number is a combination of 9 elements from a set of 13 elements(13 is the number of problems that the student has figured out how to do).

Now, m = 13, n = 9. The number of desired possibilities is:

The probability is the number of desired possibilities divided by the number of total possibilities. So

The probability the he or she will answer correctly is 1.5%

75%

step-by-step explanation:

38.6°

step-by-step explanation:

resultant is 10 pound

smaller force = 8 pound

angle formed = tan⁻¹(

                        =tan⁻¹(

                          =tan⁻¹(0.8)

                        =38.6°