Sunday, October 28, 2007

Math Test Tomorrow

Ive been studying like mad so Im getting more comfortable with stuff, but this one problem is making me batty.

A newspaper advertises 5 different movies, 2 plays, and 3 baseball games for the weekend. If a couple selects 3 activities, find the probability that one of each will be selected.

They dont want to know all the different combinations that can be had (which I am now good at) they want the probability of each but then what, multiply that together?

5/30 * 2/30 *3/30 no that doesnt work. what do I do? what is the formula for this. Im looking thru the book and cant find one explanation. BAH!

9 comments:

Unichorn said...

I'm sorry, this is not my cup of tea (or: just to lazy to figure it out now). I wish you all the luck tomorrow though. I bet you'll do fine!

~jolene said...

I would say they are probably going to spend the weekend saying: "I don't know, what do you want to do?"....as you can tell, I am an artist, not good at math...zero percent possibility I will ever be good at math ;-) Good luck SuzieBlu...you inspire me 100% of the time.

Anonymous said...

50% chance of selecting the movie, 20% chance of selecting the play and 3-% chance of selecting the baseball game.

Susan Ramey Cleveland said...

I'd say it all depends on what the couple likes to do. They might hate baseball. There might not be a movie that interests them. The theatre tickets might be outrageously expensive. I mean, what kind of dumb question is this?

Anonymous said...

This is why I went to journalism school! ;)

Thanks, Suziblu, for linking me on your blog...your kind words mean SO much!

Dawn
dblogala.typepad.com

Anonymous said...

Probability is the same as asking "what are the odds of" so as there are (5+2+3 =10) items.think of the items as a 10 spot dice where 5 spots=50% or a 1 in 2 chance and 2 spots= a 1 in 5 chance and 3 spots= a 1 in 3.33 recouring chance. But what the odds of gettin 1 of each item after 3 throws has thrown me. I'll have to think about it a bit more. Too late to help you anyway but thought this may help a little with how you think about probability.

Tarnok said...

Suzi! So sorry I havn't responded! I hope you did ok on the math test :( I was away at a viewing/funeral all week. No chance to check my mail!

I did try a few techniques but I would like to know what the answer is before I post my solution becasue I dont want to post something thats wrong and mess you up. Is the answer in the back of the book?

Again im sorry I havnt tried to help you sooner!

Anonymous said...

My explanation of the proablility:

Consider a simple case chose a movie(5 out of 10 choices or .5 (50%) probability), then a game, then a play. The probability is 0.5x0.3x0.2 or 0.03 (3% chance).

For the full problem; there are 6 ways (3x2x1 or 3! if your text includes some combinatorics) to chose a game, play and movie if the order doesn't matter. All the combinations have the same probability so the total is 6x0.03 or 18%.

Tarnok said...

I got 18% in one of my methods. (The first time I did It I used a complex method that eliminated an option everytime a choice was made, I was getting weird numbers so thast why I wanted to see the answer before I posted it out, seeing that somone else got a similar answer from a much simplier method I abondoned the other one and hope was able to explain it another way.)

Speical thanks goes to the guy/girl who posted above me!
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You have 10 activities in total. You get the probability of each one and multiply them as follow:

P(average) = Pmovies * Pbaseball * Pplays

P(a) = (5/10)*(3/10)*(2/10)
P(a) = 30/1000 = 3/100

Now the probability to chose one activity from each option in any order in 3 choices is:

3 * P(a)
2 * p(a)
1 * P(a)

or (3!) * P(a) = 18/100 = 18%
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Is this the right answer Suzi?