probability... (1 Viewer)

[lookoutastroboy]

There is a spinner. It has 12 slots with 4 1s, 2 2s, 3 3s, one 4, one 5 and one 6. What is the probability of at least two different scores?



This is an elementary question from Yr 10 but i figured people from this forum would have little trouble to tackle it. If you can, please explain it in detail in how you got the answer =)










Thanks, lookoutastroboy

 

[kurt.physics]

There is a spinner. It has 12 slots with 4 1s, 2 2s, 3 3s, one 4, one 5 and one 6. What is the probability of at least two different scores?



This is an elementary question from Yr 10 but i figured people from this forum would have little trouble to tackle it. If you can, please explain it in detail in how you got the answer =)

Thanks, lookoutastroboy

Hey, Probability is not my best maths subject (nor my favourite) but i think i may be able to help. This is what i think.

First i tryed to do a tree diagram but with all those 12 numbers it got so messy, so i thought that i would try grouping all the 1s and 2s etc. So i come up with a simple tree diagram to work with. I would simply put the group probabilities together, ie the probability of getting a one is 4 times 1/12 (ie 4/12 = 1/3) and so forth.

First we will find the probability of getting two same numbers in a row. From the tree diagram it is

(4/12)² + (2/12)² + (3/12)² + 3 times (1/12)²

= (1/3)² + (1/6)² + (1/4)² + 3 times (1/12)²

= 1/9 + 1/36 + 1/16 + 1/48

= 2/9

This is the probability of getting two the same, so the probablility of getting two different will be

1 - 2/9

= 7/9


thats what i think, anyone else agree?

edit: Just note that we square the fractions because it is really (example) 1/3 times 1/3 from the probability tree.

 

[lookoutastroboy]

solution btw if you want to attempt the question is 271/288.


kurt physics, im currently looking through your working out and thanks for atttemtping it.

if anyone else wants to have a go at getting the solution with a detailed working out, feel free.










thanks, lookoutastroboy






thanks

 

[kurt.physics]

solution btw if you want to attempt the question is 271/288.


kurt physics, im currently looking through your working out and thanks for atttemtping it.

if anyone else wants to have a go at getting the solution with a detailed working out, feel free.

Okay, yeh, i see in the MX1 forum. I thought that the question didnt seam right, so i just made an assumption that it spun twice and not three times.

Edit: Although it does seam that my work out was right under the assumption.