Official Quant thread for CAT 2013

MBA CAT 2024
24948

A cubical die is thrown and the outcomes p,q,r,s are noted what is the chance that

p
24949

@pankaj bro please also describe the process that i have to follow for the sonia's question

24950
@pankaj1988 said:
An intelligence agency forms two digit code consisting of distinct digits selected from 0 through 9 such that first digit is not 0. Some codes, when hand written on slip, can however potentially create confusion when read upside down- for example 61 may appear as 19. Find the number of codes for which there is no confusion.a)73 b)70 c)71 d)67No OA
73?
24951
@uditultimate said:
@pankaj bro please also describe the process that i have to follow for the sonia's question
I couldn't deduce any short approach to the question. Kept on deducting the numbers until left with 121 in the end. If you want I can write down the series at each step.

24952
@Logrhythm
just make the grid as below and check the smallest number that can be formed in every column. And every number in the column below this number is formed by just adding 5 to it and hence possible. Remaining (non-highlighted) numbers are not possible to be written in desired format of 13x + 5y + 17z.

I hope it is clear.

And how to highlight the achievable ones is not difficult at all as it just needs your little comfort with numbers. :)

Team BV - Kamak Lohia

Thanks Pratik...
24953
@albiesriram said:
A cubical die is thrown and the outcomes p,q,r,s are noted what is the chance thatp
C(9, 4)

Tean BV - Kamal Lohia
24954
@albiesriram said:
A cubical die is thrown and the outcomes p,q,r,s are noted what is the chance thatp
6c4 for all different

when 2 are equal -> 6*5c2*4!/2!

when three are equal -> 6*5c1*4!/3!

when all are equal -> 6

total = 861

so prob = 861/6^4 = 861/1296 = 287/432 ??

i am not sure though...


missed a case...reposting...
24955

let p, Q,R,S

where , Q= q+1, R=r+2,, S=s+3
then the condition reduces to
p
hence 9c4 , chances is 9c4/6^4
24956
@bodhi_vriksha said:
C(9, 4)Tean BV - Kamal Lohia
@Logrhythm said:
6c4 for all differentwhen 2 are equal -> 6*5c2*4!/2!when three are equal -> 6*5c1*4!/3!when all are equal -> 6 total = 861so prob = 861/6^4 = 861/1296 = 287/432 ??i am not sure though...
sir, what is wrong with my approach??

PnC mein kaafi kamzor hun mein.. :(
24957
@Logrhythm said:
6c4 for all differentwhen 2 are equal -> 6*5c2*4!/2!when three are equal -> 6*5c1*4!/3!
Arrangement is confusing. we cant just arrange the rest since there is a condition given that p
correct me if i am wrong.
24958
@Logrhythm said:
6c4 for all differentwhen 2 are equal -> 6*5c2*4!/2!when three are equal -> 6*5c1*4!/3!when all are equal -> 6 total = 861so prob = 861/6^4 = 861/1296 = 287/432 ??i am not sure though...
You missed the cases when two are equal and other two are equal. Think :)

Team BV - Kamal Lohia
24959
@Logrhythm said:
1) 3x+5y+7z = (4k-1)x + (4k+1)y + (4k+3)z so all numbers possible > 4.

bhai can you please tell me why you have written in 4k-1,4k+1... form...what does it signify..???


24960
@bodhi_vriksha said:
C(9, 4)

Tean BV - Kamal Lohia
Sir iska exact appoach batao na??
24961
Find the value of angle a in the triangle??
24962
@heylady said:
Find the value of angle a in the triangle??
a=30 ??
24963
@albiesriram let me repost my approach...now the correct one

all different -> 6c4 = 15..

two same and two different -> 6*5c2 = 60

two same and other two also same -> when one set is of 6 --> 5 cases
when one set is 5 --> 4 cases
.
.
when one set is 2 --> 1 case
total = 15 cases

three same -> 6*5c1 = 30

all same -> 6

total = 15+60+15+30+6 = 126

so, prob = 126/6^4

thanks @bodhi_vriksha (kamal sir) :)
24964
@Dexian said:
Sir iska exact appoach batao na??
Let me take some example:

Find the number of four digit numbers abcd such that a
Clearly a, b, c, d are distinct positive integers varying from 1 to 9.
So they can be selected in C(9, 4) ways and arranged in one possible arrangement only. Thus required numbers are C(9, 4)

Next now..Find the number of four digit numbers abcd such that a ≤ b ≤ c ≤ d.
Now the a, b, c, d can be equal also. So to remove the equality part see the trick carefully.
We know that a ≤ b, can you tell me smallest number which is certainly greater than a.
........
........
It is b + 1, I don't know whether you guessed it correctly or not.

Anyway now I can write that a ≤ b is equivalent to a
Similarly, extending this, the given inequality can be re-written as a And you just need to select four distinct positive integers from 1 to 12.
And this can be done in C(12, 4) ways.

Team BV - Kamal Lohia

24965
@albiesriram said:
A cubical die is thrown and the outcomes p,q,r,s are noted what is the chance thatp
all equal = 6
2 equal = 6C3*3 = 60
3 equal = 6C2*2 = 30
2 - 2 equal = 6C2 = 15
all different = 6C4 = 15

total = 126
24966

Ext. Qs. A cubical die is thrown and the outcomes p, q, r, s, t are noted what is the chance that p ≤ q ≤ r ≤ s ≤ t?


Team BV - Kamal Lohia

24967
@uditultimate said:
Q:Sonia ghandi wants to elect a president for the congress .there are 313 candidate for this post . sonia will follow foll0wing strategies :a) She asked all the candidate to be in a single row from 1 to 313.b) Firstly she deduct every person that are on alternate position but start from 2 (i.e. remove 2,4,6)c) at the instance when she reach at the extreme right end then she start the same process in the same order as left 313 and start to deduct from 311 to on and on .q) IF sonia wants that manmohan singh will become the presindent then on which position manmohan singh have to be stand.puys please solve it it stuck ...
isn't it 41?