Oxford MAT 2013/2014

I got the same thing for iii), but I'm not sure about ii. If she has 3 and Bob has 2, she knows she has 3 after looking at Bob because it can't be 1. I thought it was Alice: 5

In both cases (Bob: 4/Bob:6), she would have 2 primes to choose from, therefore she doesn't know.

Yep and Alice, being the great logician that she is, would know that Bob therefore must be 4 if she was 3 by deducing from your reason above.

Reply 1421

1298977

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Original post by pranay1995

Computer science applicants..what were your answers to q6..

Original post by Yezi_L

I just got:
ii) Alice:3 and Bob:2
iii) Alice is 4

Correct me if I'm wrong :smile:

Original post by yl95

I thought Alice was 5?

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Original post by nZeac

I got the same thing for iii), but I'm not sure about ii. If she has 3 and Bob has 2, she knows she has 3 after looking at Bob because it can't be 1. I thought it was Alice: 5

In both cases (Bob: 4/Bob:6), she would have 2 primes to choose from, therefore she doesn't know.

Math applicant, but I always like Q6! Here's what I got:

Spoiler

Reply 1422

pranay1995

Original post by souktik

Math applicant, but I always like Q6! Here's what I got:

Spoiler

can you confirm answers to q5?

Reply 1423

1298977

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Original post by pranay1995

can you confirm answers to q5?

9, n+1, (n+1)(n+2)/2, 10, 30, 13500.

Reply 1424

Alexbenfield123

2

Maths

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Reply 1425

Yezi_L

Original post by yl95

I thought Alice was 5?

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Original post by nZeac

I got the same thing for iii), but I'm not sure about ii. If she has 3 and Bob has 2, she knows she has 3 after looking at Bob because it can't be 1. I thought it was Alice: 5

In both cases (Bob: 4/Bob:6), she would have 2 primes to choose from, therefore she doesn't know.

Original post by souktik

Math applicant, but I always like Q6! Here's what I got:

Spoiler

Oops! Sorry for that silly mistake, Alice is 5 for ii). You're all right :tongue:

Sadly, I didn't get to do this question either...

Reply 1426

pranay1995

Is the cutoff for only computer science applicants always high?

Reply 1427

Arcane1729

12

Original post by souktik

9, n+1, (n+1)(n+2)/2, 10, 30, 13500.

Soutik I got all of those except 30- it really is unfair because that question was ambiguous. I thought it meant there was at least one 5 in it. so..

5_ _
_ 5 _
_ _ 5

are only configurations. 4 ways to add up to three each since total is 8

so 4*3=12

If I lose marks for this it is really unfair.

Reply 1428

'murica1776

For the last multiple choice, how come it wasn't just a geometric series? If you sketch out the graph of floor(2^x) it's a staircase starting at 1 and increasing exponentially (i.e. it takes values of 1,2,4,8), and furthermore, all of those steps last for one unit on the x-axis. So, interpreting the integral as the area under the curve, you add up all those bars, and would it not just be the sum from 0 to n of 2^n, which equals (2^n)-1?

Reply 1429

'murica1776

Original post by souktik

9, n+1, (n+1)(n+2)/2, 10, 30, 13500.

What do you think the mark scheme for this question would be? Would it be fair to say that I can get 7 points for parts 1,2 and 6?

Reply 1430

1298977

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Original post by nahomyemane778

Soutik I got all of those except 30- it really is unfair because that question was ambiguous. I thought it meant there was at least one 5 in it. so..

5_ _
_ 5 _
_ _ 5

are only configurations. 4 ways to add up to three each since total is 8

so 4*3=12

If I lose marks for this it is really unfair.

I sympathize, but I don't think they'll award you marks. It probably carries just a couple of marks, so I don't think it's going to make a huge difference either.

Original post by 'murica1776

What do you think the mark scheme for this question would be? Would it be fair to say that I can get 7 points for parts 1,2 and 6?

Yeah, you'll probably get 7 or 8. As for your doubt regarding the MCQ, I would like to point out that the function can take values between two powers of 2 as well. For example, the value is 3 between x=log_2(3) and log_2(4).

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Reply 1431

President Snow

17

Original post by 'murica1776

For the last multiple choice, how come it wasn't just a geometric series? If you sketch out the graph of floor(2^x) it's a staircase starting at 1 and increasing exponentially (i.e. it takes values of 1,2,4,8), and furthermore, all of those steps last for one unit on the x-axis. So, interpreting the integral as the area under the curve, you add up all those bars, and would it not just be the sum from 0 to n of 2^n, which equals (2^n)-1?

Because the floor function operates on the output, therefore the y-axis needs to go up in integers therefore the x-axis involves logs.

Reply 1432

Arcane1729

12

Original post by Noble.

...

Noble- when will we be invited to interview?

Reply 1433

Noble.

17

Original post by nahomyemane778

Noble- when will we be invited to interview?

End of November and early December. Expect to hear back ~2 weeks before interviews begin. :smile:

Reply 1434

msmith2512

1

Original post by Tarquin Digby

https://www.maths.ox.ac.uk/system/files/attachments/test13.pdf

Paper's up. I got ACCBDADBBB for multiple choice.

Seems this post has been now been edited to give all the right answers. Does this mean you have a hot line to the markers to change your answers as well?

Reply 1435

TheGoldenRatio

1

any got hold of the paper yet if so please link me to it

Reply 1436

1298977

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Original post by TheGoldenRatio

any got hold of the paper yet if so please link me to it

Look at the post just above yours. :tongue:

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Reply 1437

TheGoldenRatio

1

Original post by souktik

Look at the post just above yours. :tongue:

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fml, i am soooo blind! :colondollar:

, though any unofficial solutions in one please rather than all over the place!

(edited 10 years ago)

Reply 1438

1298977

1

Original post by TheGoldenRatio

fml, i am soooo blind! :colondollar:

, though any unofficial solutions in one please rather than all over the place!

Sorry, I don't think you'll get that. :tongue:

If you go through my posts you'll find solutions to problems 2, 4 and 5. I don't think I posted 3, but some others did. In case you applied to one of the CS courses, I even posted the solution to problem 6.

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