Question 443601
 <pre><font face = "Tohoma" size = 4 color = "indigo"><b> 
Hi
A quiz consists of 20 multiple-choice questions, each with 5 possible answers
 P(passing) if the minimum passing grade is 70 %. |that is, 14 or more correct
Note: The probability of x successes in n trials is: 
P = nCx* {{{p^x*q^(n-x)}}} where p and q are the probabilities of success and failure respectively. 
In this case p = 1/5 = .2 and q = .8
nCx = {{{n!/(x!(n-x)!)}}}
For example:
 P(x = 14) =  30C14(.2)^14(.8)^6 = 38,760(.2)^14(.8)^6 = .0000016647
 P(x &#8805; 14) = P(14)+P(15)+P(16)+P(17)+P(18)+P(19)+P(20) = .000001845