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Went for my SMU economics interview today

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Old 10-04-2012, 04:22 PM   #46
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more challenging qn (smu shld use it for their scholarship interview)

You leave your apartment groggily one morning, closing the door behind you. Suddenly, you are hit bya terrifying question: Do you have your keys, or are you now locked out?

You stand there thinking about it for a few seconds, before deciding that yes, you probably have your keys, further estimating that 80% of the time, you have them. You also decide that there is an equal chance of your keys either being in your left pocket or your right pocket, and if they arenít in either pocket then you donít have them at all.

Slowly, perversely enjoying the sweat, you slide your hand into your right pocket, and find that your keys are not there. What should you now think is the probability that your keys are in your left pocket?
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Old 10-04-2012, 04:25 PM   #47
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why do u guys pull the overall % of the whole. The interviewer ask u wan to go 1 or 2 to pick for the white ball. Your logical ans will be 2.

If he ask why. See below:

There is only 2 choice. First or Second.

If you take First = You are trying your luck for 33.3% chance to win.

If you take Second = You are a more logical person. You give up 33.3% for a 50% to win at the second turn.

However, overall. The % of picking the freaking white ball is still equal, but it will be more advantage to the SECOND PERSON WHO PICK.

1st= 33.3%
2nd = 50%
3rd = 33.3%

Get it?

Last edited by LokiTay; 10-04-2012 at 04:37 PM..
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Old 10-04-2012, 04:40 PM   #48
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more challenging qn (smu shld use it for their scholarship interview)
0.4?

10char
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Old 10-04-2012, 04:43 PM   #49
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.... like monty hall question sia
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Old 10-04-2012, 04:45 PM   #50
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The chances for the person to pick the ball is 50-50. But we need to bear in mind that the chances he can get to pick the balls is 66.6%

In reality it's still 33.3%
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Old 10-04-2012, 04:50 PM   #51
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more challenging qn (smu shld use it for their scholarship interview)
Lol, 50 percent lerhs bro. Either u have it or not. Just a whole wot to disorientate u niah.
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Old 10-04-2012, 04:54 PM   #52
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Why? bcos if u let others go first, and they pick the white ball, ur left with only 2 black balls?

or u mean there can be more than 1 winner?

The interviewer asked a question to all 8 of us, if you have a cup with 1 white ball and 2 black balls, and it is a competition. Person who picks the white ball wins. Would you go first or go second?

The rest all give very cock reason like i will share the winnings etc etc
I tried to be different from the rest and I answered "it dosent matter which, same chance of winning." when the interviewer asked why, i tell him gut feeling LOL. After i explain becase it dosent matter what colour ball the first person got, because there is only 1 white ball in total. After that i worked out the probability in front of everyone.

SAKTI a not??! Got chance they will accept me?

I did screw up the front part because i volunteered to go first and describe myself. Got nothing to say
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Old 10-04-2012, 04:55 PM   #53
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nopee

.................
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Old 10-04-2012, 04:56 PM   #54
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more challenging qn (smu shld use it for their scholarship interview)
Cannot give tt kind of qn la. The professor korean i tell u he asked the question at first nObody understood lol! Chui make it eben more cheem rly cannot make it his accent n other things
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Old 10-04-2012, 05:00 PM   #55
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Lol, 50 percent lerhs bro. Either u have it or not. Just a whole wot to disorientate u niah.
haha nope, wrong answer
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Old 10-04-2012, 05:01 PM   #56
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why do u guys pull the overall % of the whole. The interviewer ask u wan to go 1 or 2 to pick for the white ball. Your logical ans will be 2.

If he ask why. See below:

There is only 2 choice. First or Second.

If you take First = You are trying your luck for 33.3% chance to win.

If you take Second = You are a more logical person. You give up 33.3% for a 50% to win at the second turn.

However, overall. The % of picking the freaking white ball is still equal, but it will be more advantage to the SECOND PERSON WHO PICK.

1st= 33.3%
2nd = 50%
3rd = 33.3%

Get it?
sorry but what is this IMBA logic that I cannot understand?

why 3rd is 33.3% instead of 100%?
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Old 10-04-2012, 05:03 PM   #57
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ya lor, 3rd is jitao no choice liao, lan lan like a sinkie, have to eat whats given to him, be it black or white
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Old 10-04-2012, 05:09 PM   #58
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sorry but what is this IMBA logic that I cannot understand?

why 3rd is 33.3% instead of 100%?

You really cannot understand, its ok. The fact that the SMU interview says nothing about going third speaks for itself?

LOL.

Anyway putting caculations aside. Just going by pure logic.

You pick first. Out of 3 Balls, you pick one. 33.3% chance to get the white ball

You pick second. You forgo the first 33.3% chance to pick. Which means you have a 66.6% chance that he will fail. And then out of 2 balls remain, you have a 50% chance of getting the white ball.

You pick Last. Your % is the same as the First. Bcos like how the first have 3 balls to choose, you have the last ball given to you. 33.3%

Last edited by LokiTay; 10-04-2012 at 05:18 PM..
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Old 10-04-2012, 05:18 PM   #59
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why do u guys pull the overall % of the whole. The interviewer ask u wan to go 1 or 2 to pick for the white ball. Your logical ans will be 2.

If he ask why. See below:

There is only 2 choice. First or Second.

If you take First = You are trying your luck for 33.3% chance to win.

If you take Second = You are a more logical person. You give up 33.3% for a 50% to win at the second turn.

However, overall. The % of picking the freaking white ball is still equal, but it will be more advantage to the SECOND PERSON WHO PICK.

1st= 33.3%
2nd = 50%
3rd = 33.3%

Get it?
Logical...

if first to take, 1/3 of the chances,
if 2nd to take left 2 ball, which is 50% chance
if 3rd to take left 1 ball, which is 1/3 chance that u will be the last to take and still obtain the white ball.
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Old 10-04-2012, 05:23 PM   #60
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Logical...

if first to take, 1/3 of the chances,
if 2nd to take left 2 ball, which is 50% chance
if 3rd to take left 1 ball, which is 1/3 chance that u will be the last to take and still obtain the white ball.
ya i got it...

but provided when they open the cup to reveal the ball also need to be taken into consideration leh

1st to take sure 1/3 chance
2nd to take, is 50% chance provided 1st open and reveal wad ball he took
3rd to take, is 1/3 chance provided non of the balls are revealed yet
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