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!


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?" you can tell, I am an artist, not good at percent possibility I will ever be good at math ;-) Good luck 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!


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!

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%

Is this the right answer Suzi?