Stuck?? Probability Question (1 Viewer)

[FcUk]

use a tree diagram.

tried that still doesnt work i dont even know what to do if im using the tree diagram

 

[sub]

use the tree for all results. count the no. of times a tie can happen, and put it over the total no. of results.
for who wins outright, just count up how many times each can win... the higher one has more of a chance.
hope that helped

man...u just paraphrased what i sed....i guess i should stop spamming on this thread...
back to more papers...goodluck tomoro

 

[Binky]

well in terms of getting a tie, the number would have to be both even and over six, and with the numbers you've been given (1,2,3,4,5) you would have to add 5 + 3 to get 8 (the only number that could be a tie).
so the chance of one of those cards (the 3 or 5) being pulled the first time would be 2/5. the chance of the second card (3 or 5, depending on what's left over) being pulled is 1/4 (because there's no replacement.)
multiply and you get 1/10

 

[Dougie]

ok...
2 cards from the choice of 5 (1,2,3,4, and 5) right.
start with 1, then the only other choices r 2,3,4, or 5. ie. 3,4,5, or 6 once added.
do the same with the other numbers...
start with 2, then 1,3,4, or 5. ie. 3,5,6 or 7.
3, then 1,2,4,5 ie. 4,5, 7,8
4, then 1,2,3,5 ie. 5,6,7,9
5, then 1,2,3,4 ie. 6,7,8,9.

need more help?

 

[FcUk]

Thanks sub a dougie now i get it i think hah nah i do still uncertain bout probability but thanks for the help anyway

 

[sub]

binky nice idea, but one problem....u can pick the other first....its supposed to be 2/5 * 1/4.

the first choice can be a 3 or a 5, ie a probabiltiy of 2/5...the rest is right

 

[Tommy_Lamp]

Do a tree diagram.
If the first card picked is 1, then the 2nd card picked can be 2,3,4 or 5
If the first card picked is 2, then the 2nd card picked can be 1,3,4 or 5
If the first card picked is 3, then the 2nd card picked can be 1,2,4 or 5
If the first card picked is 4, then the 2nd card picked can be 1,2,3 or 5
If the first card picked is 5, then the 2nd card picked can be 1,2,3 or 4

Then you add up each possibilty, there are twenty total possibilites.
The amount of times that the total number of the 2 cards picked is greater then 6 and even is 2, when 8 is the final answer.
Hence 2/20 = 1/10

 

[Binky]

so what about doubling it then?
whaatt i'm so confused
fuck i'm gonna give up soon lol

 

[sub]

dude it is 1/10
2/5*1/4 = 1/10

 

[Dougie]

no worries mate, any time, mesg me if u still don't get it. otherwise good luck

 

[sub]

look once more...slowly:
u have to choose a 5 or a 3:

now u can choose either a 5 or a 3 first up: ie prob of 2/5 (five cards)
next u choose the remaining card: 1/4 - cos no replacement

that way u dun gotta double later

hope that clears everything up binky

 

[Binky]

ok some people are saying it's 1/5x 1/4 + 1/5x 1/4
others are saying it's just 2/5x 1/4

both equal 1/10

which one is it?????

 

[Tommy_Lamp]

You can do it different ways.

 

[sub]

ends up with the same result...choose whichever suits u, with the explanation, and use that one in te exam.

its two methods for doing the same question...dont stress out.

 

[xprshn]

I agree with part ii) that they both have equal chances, but are you sure its 3/10 ?

 

[rolo]

ii

i got them being equal prob too, but the answer is 2/5.