Friday, January 20, 2006

Compound Probability

Today we learned how to find the probability of compound events. A compound event occurs when more than one thing is happening.

Example: A number cube is rolled and a coin is tossed. What is the probability that you will roll an even number and get tails?

To work this problem, you would first find the probability of each event.
P(even number)= 3 out of 6 = 1/2
P(tails) = 1/2

Then you should multiply these probabilities to find the compound probability.
1/2 X 1/2 = 1/4

Sometimes the probability of the second event depends on the first event.

Example: There are 8 marbles in a jar. Four are orange, and three are black. What is the probability of drawing two orange marbles if the first marble is not replace?

P(first orange) = 4/8 = 1/2
P(second orange) = 3/7 (There is one less orange and one less total.)
You would still multiply the two probabilities.
P(orange, then orange) = 1/2 x 3/7 = 3/14

Tonight's homework....
Math: pp. 400-401, #6-9, 11-16, 19-21, 25-32
Pre-Algebra: pp. 653-655, #11-28, 33, 34, 50


At 1:13 AM, Anonymous Anonymous said...

So does this mean there is homework on Friday's? And is this due Monday?

At 7:48 AM, Blogger Mrs Simpson said...

Yes...but I am taking a personal day Monday to go to a funeral, so this time you get an extra day.

At 3:40 PM, Anonymous Anonymous said...

This blog is really helping me. I thank you for posting the homework as well.I'm sorry your friend has died be careful. See you Tuesday!!


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