SOLUTION: What's the probability of a student having a x cell phone, if it is given that he has a y cell phone? There are 1000 students, 420 have x cell phones, 580 have y cell phones, an

Algebra ->  Probability-and-statistics -> SOLUTION: What's the probability of a student having a x cell phone, if it is given that he has a y cell phone? There are 1000 students, 420 have x cell phones, 580 have y cell phones, an      Log On


   

Question 863100: What's the probability of a student having a x cell phone, if it is given that he has a y cell phone?
There are 1000 students, 420 have x cell phones, 580 have y cell phones, and 80 have both
Found 2 solutions by jim_thompson5910, ewatrrr:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
There are 80 people who have both x and y types. This is out of 580 people who have type y phones. So the answer as a fraction is 80%2F580+=+4%2F29

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

P(A|B) = P(A and B)/P(B)

P(x |y = %2880%2F1000%29%2F%28580%2F1000%29+=+80%2F580+=+4%2F29