Hi,

Note: The probability of x successes in n trials is: 

P = nCx*  where p and q are the probabilities of success and failure respectively. 

In this case p(failing) = .20 and q(passing) = .80   |the failure rate is 20%.

nCx = 

Of 15 students registered in the freshman class;

 P(all pass) = (.80)^15 = .0352

P(at least 1 fails) = 1 - P(none failing) = 1 - .0352 = .9648

How many freshman are likely to pass? .80*15 = 12



An algebra class has 18 girls and 14 boys. 

Five tickets to a concert have just been made available to the class. 

The students to get the tickets will be chosen at random.

What is the probability that:

a) five girls are chosen = 18C5/32C5 = 8568/201,376 = .0425

  nCx =   18C5 =  18!/(5!13!) and 32C5 = 32!/5!27!

These can be found with a calculator that has a factorial function.



b) five boys are chosen = 14C5/32C5 = 2002/201,376 = .0099

c) at least 1 girl is chosen? 1 - P(all boys) = 1 - .0099 = .9901

d) How many girls are likely to be chosen? (18/32)*5 = 2.8  

 

RELATED QUESTIONS

According to the college registrar's office, 50% of students enrolled in an introductory... (answered by ewatrrr)

A freshman english class at a certain college has 49 women and 20 men. If 5 students are... (answered by stanbon)

If 20 students register for a Sociology class and 35 students register for Psychology,... (answered by Edwin McCravy)

What is the age distribution of patients who make office visits to a doctor or nurse? The  (answered by richard1234)

At Newfield HS, the sophomore class has 60 more students that the freshman class. The... (answered by College Student)

“Best Fitness” Company is going to hold a stretching class with 15 registered... (answered by Boreal,ikleyn)

In a psychology class of 60 students there are 15 males and 45 females. Of the men 15,... (answered by ewatrrr)

How do you apply the Bayes' Theorem?  Thank you. 

Use Bayes Theorem for the following 
 (answered by solver91311)

Two students are registered for the same class and attend independently of each other,... (answered by LinnW)