probability (1 Viewer)

[eskimoh]

nicole and mariana play against eachother in the hrd round of the aus open. the first player to win 2 sets wins the match. the probability that nicole wins any set is 70%

a) find the probability that the game will last 2 sets only
b) find the prob . that nicole wins the match
c) find the prob. that mariana wins the match


i dont hav answers so i just wanna kno what they are?
i got:

a) 29/50
b) ??
not sure bcos there can be more than 2 sets before she wins? is there some limit to how many sets in a tennish match? (LOL sorry i dno abt tennis)
c) 1-P(nicole wins) ?

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thnx!

 

[eskimoh]

bump lol

 

[Timothy.Siu]

i think a) is 0.58
probability that it doesn't last 2 sets is
(0.7x0.3)x2
so 1-0.42 is 0.58
or u cud just do 0.7*0.7+0.3*0.3
b)umm probability she doesn't is 0.3x0.3+(0.3x0.7x0.3)x2
1-that is 0.784
or 0.7*0.7+2x(0.7*0.3*0.7)=0.784

c) 1-0.784=0.216

 

[lyounamu]

nicole and mariana play against eachother in the hrd round of the aus open. the first player to win 2 sets wins the match. the probability that nicole wins any set is 70%

a) find the probability that the game will last 2 sets only
b) find the prob . that nicole wins the match
c) find the prob. that mariana wins the match


i dont hav answers so i just wanna kno what they are?
i got:

a) 29/50
b) ??
not sure bcos there can be more than 2 sets before she wins? is there some limit to how many sets in a tennish match? (LOL sorry i dno abt tennis)
c) 1-P(nicole wins) ?

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thnx!

I think a) is correct.

b)
Nicole winning:

nC2 . 0.3^(n-2) . 0.7^2

c)
Mariana winning:

nC2 . 0.7^(n-2) . 0.3^2

 

[crammy90]

i)
2 sets = P(nicole wins) + P(mariana wins)
= (.49) + (.147)
= .58

ii)
now after they have played 3 sets some1 has to have won at least twice...
= P(.49) + P(.147) + P(.147)
= 98/125

ii)
P = 1- (98/125)
= 27/125

thats how i understood it anyways
same answers as above

 

[lyounamu]

i)
2 sets = P(nicole wins) + P(mariana wins)
= (.49) + (.147)
= .58

ii)
now after they have played 3 sets some1 has to have won at least twice...
= P(.49) + P(.147) + P(.147)
= 98/125

ii)
P = 1- (98/125)
= 27/125

thats how i understood it anyways
same answers as above

Are we assuming that the game only lasts 3 games?

 

[dolbinau]

I agree with you Timothy.Siu

The way I understand it, as soon as someone gets 2 sets the game is over.

So the way she can win is

LWW
WLW
WW (end of game)

It's not an assumption though, it says the first one to get 2 sets wins, and these are the only ways it can happen.

 

[lyounamu]

I agree with you Timothy.Siu

The way I understand it, as soon as someone gets 2 sets the game is over.

So the way she can win is

LWW
WLW
WW (end of game)

It's not an assumption though, it says the first one to get 2 sets wins, and these are the only ways it can happen.

What are you on about? What if the number limit of the games can get over 3?

You can have LLLLWW or LLLWW or LWLLLLLLW

 

[crammy90]

What are you on about? What if the number limit of the games can get over 3?

You can have LLLLWW or LLLWW or LWLLLLLLW

the game can only last 3
look at a tree diagram...by the third set some1 has already won 2 sets

 

[lyounamu]

the game can only last 3
look at a tree diagram...by the third set some1 has already won 2 games...

Where in the question said that?

 

[Darnie]

What are you on about? What if the number limit of the games can get over 3?

You can have LLLLWW or LLLWW or LWLLLLLLW

nah, cause if she loses two in a row she loses the match eh.
so you can have WLW, LWW, LL, WW, LWL, WWL, ETC.

 

[lyounamu]

nah, cause if she loses two in a row she loses the match eh.
so you can have WLW, LWW, LL, WW, LWL, WWL, ETC.

Ok, fair enough.

I forgot that.

 

[crammy90]

the first player to win 2 sets wins the match.

notice some1 has won either way over 3 sets

 

[old.skool.kid]

Yeah womens tennis only has 3 sets.

 

[syriangabsta]

i think a) is 0.58
probability that it doesn't last 2 sets is
(0.7x0.3)x2
so 1-0.42 is 0.58
or u cud just do 0.7*0.7+0.3*0.3
b)umm probability she doesn't is 0.3x0.3+(0.3x0.7x0.3)x2
1-that is 0.784
or 0.7*0.7+2x(0.7*0.3*0.7)=0.784

c) 1-0.784=0.216

hey i have a q regarding your working..its probably something really stupid that im not noticing. but eh. why are you multiplying stuff by 2?
thanks

 

[Timothy.Siu]

hey i have a q regarding your working..its probably something really stupid that im not noticing. but eh. why are you multiplying stuff by 2?
thanks

lol, sorry, i'm not really sure how ur supposed to do probability but i multiplied it by two because the probability of nicole winning and first and then losing the second is the same as nicole losing the first and winning the second, sorry that it wasn't clear. my working out is usually bad/hard to understand.