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Posers and Puzzles

Joined 16 Dec '04 Moves 2433 this is an easy one,
you have 2 jars & 100 marbles, 50 red and 50 blue.
you have to place the marbles into the jars such that you maximise the likelihood that you pick out a red marble.
i can get almost 3/4 or 75% likelihood.

Out of my mind

Joined 25 Oct '02 Moves 20443 1 red marble in jar 1 and the rest in jar 2 gives about 3/4 chance...74/99 to be precise
put x red marbles in jar 1 along with y black ones.
With chance 1/2 you pick a marble from jar 1, with chance x/x+y this is a red marble.
With chance 1/2 you pick a marble from jar 2, with chance 50-x/100-x-y this is a red marble.
1/2*(x/x+y + 50-x/100-x-y) = ugly
I have not the time to write ugly out, to differentiate to x and y and to see of they happen to have a common zero.

Joined 08 Jun '04 Moves 3351 Originally posted by kcams
this is an easy one,
you have 2 jars & 100 marbles, 50 red and 50 blue.
you have to place the marbles into the jars such that you maximise the likelihood that you pick out a red marble.
i can get almost 3/4 or 75% likelihood. The statement of your puzzle is incomplete. What , wherefrom and how do you pick out has to be specified.

tinyurl.com/y2c6j2t3

Joined 23 Aug '04 Moves 24791 Originally posted by kcams
this is an easy one,
you have 2 jars & 100 marbles, 50 red and 50 blue.
you have to place the marbles into the jars such that you maximise the likelihood that you pick out a red marble.
i can get almost 3/4 or 75% likelihood. Place the red marbles into both jars. Give the blue marbles to the kid down the street. 100%.

Place 25 blue marbles into each jar. Carefully, without disturbing the jars, place 25 red marbles on top of the blue marbles. 100%.

Joined 16 Dec '04 Moves 2433 Originally posted by cheskmate
The statement of your puzzle is incomplete. What , wherefrom and how do you pick out has to be specified. you pick the jar and marble at random.

Chesstralia

Joined 18 Aug '03 Moves 54533 Originally posted by kcams
this is an easy one,
you have 2 jars & 100 marbles, 50 red and 50 blue.
you have to place the marbles into the jars such that you maximise the likelihood that you pick out a red marble.
i can get almost 3/4 or 75% likelihood. ðŸ˜•

H. T. & E. hte

Joined 21 May '04 Moves 3510 Originally posted by kcams
you pick the jar and marble at random. put 1 red marble in one jar and put all the rest in the other. The probability of picking a red marble would be;

(1+49/50)/2 = 74.99%....This is the maximum that can be achieved.

Dhaka

Joined 08 Oct '04 Moves 3885 Originally posted by ranjan sinha
put 1 red marble in one jar and put all the rest in the other. The probability of picking a red marble would be;
(1+49/50)/2 = 74.99%....This is the maximum that can be achieved.
????????????
how?....

tinyurl.com/y2c6j2t3

Joined 23 Aug '04 Moves 24791 There's a 50% chance you'll pick the jar with the red marble. If you pick this jar, you'll definitely get a red marble. (1/2)
If you don't pick that jar, then you'll have a 49/100 chance of getting a red marble.
Therefore the chance of getting a red marble is 1/2 + 1/2 * 49/100 = 100/200 + 49/200 = 149/200.

Dhaka

Joined 08 Oct '04 Moves 3885 expression was to be(1+(49/100))/2

Joined 31 Oct '04 Moves 2047 Originally posted by muktadir
The second box contains 99 marbles, out of which 49 are red. Hence actually it will obviously be -

(1+49/99)/2 = 74.99%...

tinyurl.com/y2c6j2t3

Joined 23 Aug '04 Moves 24791 Originally posted by coolwarrior
The second box contains 99 marbles, out of which 49 are red. Hence actually it will obviously be -
(1+49/99)/2 = 74.99%... Oops

H. T. & E. hte

Joined 21 May '04 Moves 3510 Originally posted by muktadir
It was a case of error due to hurried thinking and typing. Coolwarrior has already posted the correct expression. Thankx.

Out of my mind

Joined 25 Oct '02 Moves 20443 Originally posted by ranjan sinha
It was a case of error due to hurried thinking and typing. Coolwarrior has already posted the correct expression. Thankx. *cough* In my days we were taught to simplify expressions like that.

Correct me if i'm wrong but it's not 74.99%

My calculation say it's 74/99 = 74.74 % approximately.

H. T. & E. hte

Joined 21 May '04 Moves 3510 Originally posted by TheMaster37
*cough* In my days we were taught to simplify expressions like that.
Correct me if i'm wrong but it's not 74.99%
My calculation say it's 74/99 = 74.74 % approximately. put x = 1, and y = 0, in the expression (=ugly) given in your earlier post.