SOLUTION: A biology gives a surprise quiz consisting of 15 multiple choice questions with 5 answer options. Assume an unprepeared student decides to randomly select answers. What is the ch

Algebra.Com
Question 247205: A biology gives a surprise quiz consisting of 15 multiple choice questions with 5 answer options. Assume an unprepeared student decides to randomly select answers. What is the chance this student has
a. The first 7 answers correct and the last three answers wrong
b. Any 7 or more of the questions correct

Answer by edjones(8007)   (Show Source): You can put this solution on YOUR website!
a. (1/5)^7(4/5)^3=.00000655...
.
b. This is too long to write out the expansion.
Let x=.2 and y=.8
expand (x+y)^15
Eliminate bits when x has an exponent of less than 7
.0181... Answer.
.
Ed

RELATED QUESTIONS

A quiz has 7 true/false questions. 8 multiple choice with 3 options each. How many... (answered by richwmiller)
An instructor gives a pop quiz consisting of 10 multiple choice questions, where each... (answered by htmentor)
An instructor gives a pop quiz consisting of 10 multiple choice questions, where each... (answered by Boreal)
A quiz consisting of of four multiple-choice questions has four available options (a, b , (answered by mykasha)
A quiz consisting of four multiple-choice questions has four available options (a,b,c, or (answered by stanbon)
A quiz consists of 15 multiple choice questions. Each question has 5 choices, with... (answered by solver91311)
If a quiz contains 5 true-false questions and 5 multiple-choice questions, each with 4... (answered by ewatrrr)
An exam has 5 True and False questions, followed by 6 multiple choice questions each with (answered by Boreal)
A multiple choice trivia quiz has 10 questions, each with 5 possible answers. If someone... (answered by ewatrrr)