SOLUTION: There are 20 red checkers and 8 black checkers in a bag. Checkers are selected one at a time, with replacement. Each time,the color of the checker is recorded. Find the probabili

Algebra ->  Probability-and-statistics -> SOLUTION: There are 20 red checkers and 8 black checkers in a bag. Checkers are selected one at a time, with replacement. Each time,the color of the checker is recorded. Find the probabili      Log On


   

Question 965656: There are 20 red checkers and 8 black checkers in a bag. Checkers
are selected one at a time, with replacement. Each time,the color of the checker is recorded. Find the probability of selecting a red checker exactly 8 times in 10 selections.
Please explain how to solve!
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Find the probability of choosing a red checker,
P%5BR%5D=20%2F28=5%2F7
So then the probability of not choosing a red checker is,
P%5BB%5D=2%2F7
Find the number of combinations for 8 red checkers in 10 selections.
C%2810%2C8%29=45
So then,
P=C%2810%2C8%29%2AP%5BR%5D%5E8%2AP%5BB%5D%5E2
P=45%2A%285%2F7%29%5E8%2A%282%2F7%29%5E2
P=%2845%2A390625%2A4%29%2F%28282475249%29
P=%2870312500%29%2F%28282475249%29
P=0.249