Learn math, science, English SAT & ACT from
highquaility study
videos by expert teachers
Learn math, science, English SAT & ACT from
highquaility study videos by expert teachers
Introduction to Probability  Problem 1
Carl Horowitz
Carl Horowitz
University of Michigan
Runs his own tutoring company
Carl taught upperlevel math in several schools and currently runs his own tutoring company. He bets that no one can beat his love for intensive outdoor activities!
Finding the probability of a situation. The general formula for finding the probability is the number of events that you’re concerned with over the total number of events in an entire sample space. What we’re looking at here is a class containing 17 girls and 13 guys and considering the probability that the teacher randomly calls on a guy.
For this kind of problem we’re going to assume the teacher is completely unbiased which of course is the case always and what we’re basically going to do is consider the number of outcomes that we want, him calling on a guy over the total number of outcomes, calling on anybody.
Pretty straight forward for this problem there are 13 plus 17, 30 people in this class which he can call on, so that’s going to be our sample space. Calling on each of those students individually, that could be 30 different outcomes. The denominator for our probability is 30. Of those we’re only concerned with the ones that are guys, of which there are 13. He calls on any one of those 13. That’s an even we want so therefore there are 13 events leaving us with the probability of 13/30 that this teacher randomly calls on a guy.
Please enter your name.
Are you sure you want to delete this comment?
Carl Horowitz
B.S. in Mathematics University of Michigan
He knows how to make difficult math concepts easy for everyone to understand. He speaks at a steady pace and his stepbystep explanations are easy to follow.
Concept (1)
Sample Problems (6)
Need help with a problem?
Watch expert teachers solve similar problems.

Introduction to Probability
Problem 1 6,816 viewsA class contains 17 girls and 13 guys.
What is the probability a teacher randomly calls on a guy? 
Introduction to Probability
Problem 2 5,957 viewsIn a target,
P(red) = 
Introduction to Probability
Problem 3 1,161 views 
Introduction to Probability
Problem 4 1,001 views 
Introduction to Probability
Problem 5 1,026 views 
Introduction to Probability
Problem 6 914 views
Comments (0)
Please Sign in or Sign up to add your comment.
·
Delete