So let's give it a try with dice ...
Each of these questions requires either the use of the OR law or the AND law. See if you can figure out which is which and find the right answer (by the time you are done with this module, you can clean up on games of chance!)
What is the chance of rolling an even number on a 6-sided die?
(To make this problem interactive, turn on javascript!)
- I need a hint ... : This is the same as rolling a 2 OR a 4 OR a 6.
- ...another hint ... :P(2 or 4 or 6) =
P(2) + P(4) + P(6) - ...another hint ... :P(2) + P(4) + P(6) = 1/6 + 1/6 + 1/6
I think I have the answer: 1/2
What is the chance of rolling 4 or less on a 6-sided die?
(To make this problem interactive, turn on javascript!)
- I need a hint ... : This is the same as rolling 1 OR 2 OR 3 OR 4.
- ...another hint ... :Since its an OR question, add the probabilities
I think I have the answer: 4/6 (= 2/3)
What is the chance of rolling a 1 twice in a row?
(To make this problem interactive, turn on javascript!)
- I need a hint ... : This is the same as rolling 1 AND then another 1
- ...another hint ... : Since its an AND question, multiply the probabilities
I think I have the answer: 1/36
Copyright University of Maryland, 2007
You may link to this site for educational purposes.
Please do not copy without permission
requests/questions/feedback email: mathbench@umd.edu