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# The Big TSA 2009 Thread watch

1. (Original post by gustman)
Hey guys, I've been doing some questions for the TSA and have a couple on the problem solving side I can't do, I would appreciate it if anyone could help.

First question:

Spoiler:
Show
The weather in a place rains on three times as many days as there are rain-free days. Luckily the daily weather forecast is fairly good. Whether the forecast is for rain or for no rain, it is correct on nine occasions out of ten.

Which one of the following is the probability that the weather forecast will predict rain tomorrow?

A. 13/20
B. 27/40
C. 3/4
D. 13/16
E. 9/10

Spoiler:
Show
D

Second question:

Spoiler:
Show
A football league is comprised of 22 teams. Over the season, each team plays each of the other teams twice (home and away). 3 points for a win, 1 for a draw and 0 for a loss. At the end of a season all the points are added up and the three teams with the lowest scores are relegated. If two or more clubs finish with same points then the goal difference is taken into account.

What is the lowest number of points that a club can get in one season and not be relegated?

A. 4
B. 5
C. 6
D. 9
E. 18

Spoiler:
Show
C

I don't get the same answers as the actual answers so I just want to know how they are done.
I should be able to help out with these. I start with the second questions though which took me 20 seconds other than the frustrating 15 minutes I spent on the first one

Second Question: You simply need to catch the question´s drift which somewhat easier when you are a keen football player. The last four teams draw all the matches they play amongst each other and lose any other. Since every endangered team will play each of the other three bottom teams twice (--> 6 matches) they will end up with 6 points each. The one team with the best or let´s say least terrible goal difference will not be relegated and stay in with only 6 points.

First Question: Is that a proper TSA question? If yes, I might as well admit I´m not smart enough and cancel my application, because this is a fairly advanced propability question..

Say the weather forecast will predict rain tomorrow with the unknown propability P.
It will thus predict dry weather with the propability Q - that is: Q=1-P

Based on the task, what is predicted will happen with a propability of 9/10. So, we can conclude:
P (rain was predicted and it actually rains) = P * 9/10
AND
P (dry weather was predicted but it rains anyway) = (1-P) * 1/10

We also know that the overall chance of a rainy day is 3/4
-->
P * 9/10 + (1-P)*1/10 = 3/4
P * 9/10 + 1/10 - 1/10*P = 3/4 | -1/10
4/5 * P = 26/40 | * (5/4)
P = 130/160 = 13/16 --> D is in fact correct

Note: I used fractions on purpose since you´re not allowed to use a calculator.

There must be an easier way to that solution but I can´t find it, sorry

I have attempted the 2008 TSA which is provided on the website and ended up with 43 correct responses (86%) in roughly 60 minutes. However, I have no idea whether that is a good score - or an average one. In fact, I am lacking any medium of comparison. Can anybody help me out?
2. (Original post by mightyduck)

First Question: Is that a proper TSA question? If yes, I might as well admit I´m not smart enough and cancel my application, because this is a fairly advanced propability question..

Say the weather forecast will predict rain tomorrow with the unknown propability P.
It will thus predict dry weather with the propability Q - that is: Q=1-P

Based on the task, what is predicted will happen with a propability of 9/10. So, we can conclude:
P (rain was predicted and it actually rains) = P * 9/10
AND
P (dry weather was predicted but it rains anyway) = (1-P) * 1/10

We also know that the overall chance of a rainy day is 3/4
-->
P * 9/10 + (1-P)*1/10 = 3/4
P * 9/10 + 1/10 - 1/10*P = 3/4 | -1/10
4/5 * P = 26/40 | * (5/4)
P = 130/160 = 13/16 --> D is in fact correct

Note: I used fractions on purpose since you´re not allowed to use a calculator.

There must be an easier way to that solution but I can´t find it, sorry
I hope that wasn't a TSA question, I haven't studied probability... Thanks for the answer though!

I have attempted the 2008 TSA which is provided on the website and ended up with 43 correct responses (86%) in roughly 60 minutes. However, I have no idea whether that is a good score - or an average one. In fact, I am lacking any medium of comparison. Can anybody help me out?
I'm sure that's a good score. The multiple choice questions are my strength (not looking forward to the essay...), and I got 46 (92%) in 70 minutes on the 2008 paper. I can't see how a score of 86% would be below average...
3. (Original post by mightyduck)
I should be able to help out with these. I start with the second questions though which took me 20 seconds other than the frustrating 15 minutes I spent on the first one

Second Question: You simply need to catch the question´s drift which somewhat easier when you are a keen football player. The last four teams draw all the matches they play amongst each other and lose any other. Since every endangered team will play each of the other three bottom teams twice (--> 6 matches) they will end up with 6 points each. The one team with the best or let´s say least terrible goal difference will not be relegated and stay in with only 6 points.

First Question: Is that a proper TSA question? If yes, I might as well admit I´m not smart enough and cancel my application, because this is a fairly advanced propability question..

Say the weather forecast will predict rain tomorrow with the unknown propability P.
It will thus predict dry weather with the propability Q - that is: Q=1-P

Based on the task, what is predicted will happen with a propability of 9/10. So, we can conclude:
P (rain was predicted and it actually rains) = P * 9/10
AND
P (dry weather was predicted but it rains anyway) = (1-P) * 1/10

We also know that the overall chance of a rainy day is 3/4
-->
P * 9/10 + (1-P)*1/10 = 3/4
P * 9/10 + 1/10 - 1/10*P = 3/4 | -1/10
4/5 * P = 26/40 | * (5/4)
P = 130/160 = 13/16 --> D is in fact correct

Note: I used fractions on purpose since you´re not allowed to use a calculator.

There must be an easier way to that solution but I can´t find it, sorry

I have attempted the 2008 TSA which is provided on the website and ended up with 43 correct responses (86%) in roughly 60 minutes. However, I have no idea whether that is a good score - or an average one. In fact, I am lacking any medium of comparison. Can anybody help me out?
For the second question, I assumed that because only three teams will be in the bottom, they will lose against all others but draw against each other so they would each have 4 points each so the next team only had to have 5 but in this situation, the 4th team from bottom will have 18 points so that wouldn't work Well your way makes a lot more sense, cheers

I didn't know how to do the first one so thanks for showing me how to do it. I never expected it to be that hard

The questions not on the TSA, thank god . I'm just doing some papers my teacher gave me. He gave me hard maths ones so I could prepare for the maths challenge on the day after the TSA. Anymore problems, I'll be sure to post them on here.
4. Grr why are you all so smart?
5. (Original post by moreiniho)
If I recall correctly, they're saying that X is responsible but that Y can only effect change. In my mind, that's wrong and can be directly attacked. If X has brought about circumstances, X can only reverse those particular circumstances. Sure Y has a role to play. But not directly.
I'm not convinced, what if a boy knocks over a chair and a girl picks it up. In this case X caused something but Y reversed it with no action from X. Does this disprove your logic?
6. (Original post by chair12345)
I'm not convinced, what if a boy knocks over a chair and a girl picks it up. In this case X caused something but Y reversed it with no action from X. Does this disprove your logic?
I think in that case you'd have to compare them as animated vs inanimate.
Otherwise you could just as easily 'disprove' the slave/slave-owner example in saying that a different slave owner could release a particular slave.

Tell me if I'm way off..
7. (Original post by chair12345)
I'm not convinced, what if a boy knocks over a chair and a girl picks it up. In this case X caused something but Y reversed it with no action from X. Does this disprove your logic?
Your analogy brings a third party into the equation; the chair. There is no 'chair' in the original statement. It's solely X and Y with no external object.
8. This thread makes me feel stupid
9. (Original post by trollman)
This thread makes me feel stupid
Same
10. Hmm...this hurts my head so early in the morning!

I'm still unsure myself but what if:
In 1832 I buy a slave but in 1833 a law is passed abolishing all slavery and therefore freeing the slave. So X (the slaver owner) created the circumstance but Y (Parliament) reversed it.
Or I buy a slave but they run away. Surely (de facto) the slave is now free without the slave owner's input. So X (the slave owner) created the circumstance but Y (the slave) reversed it.

I'm just throwing ideas around :P
11. I have been getting lots of pm's about the free q&a session.

so I'll put it on here. please delete if this is not allowed.

http://www.sucedo.com/products/tsa/question-session/
12. (Original post by jnm008)
I have been getting lots of pm's about the free q&a session.

so I'll put it on here. please delete if this is not allowed.

http://www.sucedo.com/products/tsa/question-session/
i dont understand the Q&A session, is it in person? or is it an online thing?
13. it's funny to see everyone stressing out over the TSA. i'm glad it's not just me.
14. I'm going to attempt one of the TSA tests shortly. I'm scared of failure lol
I really, really do not want to have to sit this test

Ok, I got 40/50 on the Specimen paper. It sounds ok, but I don't really know what the average is
15. ive just done the 2008 paper timed. i finished in time and got 42/50 which is equivilant to 84%: but i understand that certain questions are weighted more. so am i doing exceptional or just average? as in says on the tsa website that scores above 80 are exceptional.
cheetrs
16. (Original post by chair12345)
Hmm...this hurts my head so early in the morning!

I'm still unsure myself but what if:
In 1832 I buy a slave but in 1833 a law is passed abolishing all slavery and therefore freeing the slave. So X (the slaver owner) created the circumstance but Y (Parliament) reversed it.
Or I buy a slave but they run away. Surely (de facto) the slave is now free without the slave owner's input. So X (the slave owner) created the circumstance but Y (the slave) reversed it.

I'm just throwing ideas around :P
Like the guy said before, you're including too many variables (with the Parliament example). If you look at the situation with only two, then you have "slave owners" and "slaves." The Parliament is certainly made up of slave owners, so it is still incumbent upon the slave owners to free the slave.

Like I said before, you could take any situation given to follow this X & Y thing and introduce more variables to "disprove" it.

One counterexample, I think, is your slave running away. Or, if the slaves revolt, certainly they have enacted their own freedom?
You could argue that the slave owners have to give up to finally let them have power, but realistically that's not the case. In fact they could even switch positions given the revolt was intense enough -- then doesn't it totally disprove that X has to act to change Y, since Y becomes X effectively on its own accord?

Someone else who actually knows what they're talking about should give us some input!

EDIT:

Great, I'll be busy during the Q&A with the 100% guy. I realize it's effectively helping your competition, but we are already -- would anyone mind sharing any particular insight he gives? I would certainly like to know what he did to prepare and any specific materials he used...
17. (Original post by Mortifera)
Someone else who actually knows what they're talking about should give us some input!
Sounds good!
18. (Original post by Zhang1)
ive just done the 2008 paper timed. i finished in time and got 42/50 which is equivilant to 84%: but i understand that certain questions are weighted more. so am i doing exceptional or just average? as in says on the tsa website that scores above 80 are exceptional.
cheetrs
I'd say it's pretty damn good.
19. I am an international student, and I can't take the TSA because there aren't any centres close to me and my school couldn't register as a centre. I've already emailed the college to which I've applied, and they said that it happens a lot, but I'm still really worried that it will mean they wont even consider my application. Any advice?
20. What's the average of admitted students of Oxford PPE? 60ish? 70ish? 80ish? 90ish?(in which case I'd be dead).

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