Official Quant thread for CAT 2013

MBA CAT 2024
25668
@jain4444 said:
John has a bag of colored billiard balls which are labeled with the numbers 1,2,3,4,5,6. He reaches into the bag, draws out a ball, records down the number and then places the ball back in the bag. He does this a total of 4 times (hence has 4 numbers). The probability that at least 2 of the numbers are equal is a/b, where a and b are positive, coprime integers. What is the value of a+b?
13/18.......
13+18=31
25669
@bodhi_vriksha aint the way to solver it bro

best way always is assume the boxes to be a b c d and e

now pairs of 2 out of 5 will make ten combos

ab
ac
ad
ae
bc
bd
be
cd
ce
de

basically each box involved in 4 times
so wot we get now when we add all the ten weights is


4 ( a plus b plus c plus d plus e )
divide this by 4 and use equations accordingly to solve ahead

25670
@himanshusood5 said:
anyone wants all CL material including mock tests ( online and paper based ) and T.I.M.E mocks for a bit of money
dude they are available online....why would someone want to buy it, moreover selling stuff is against the policy of pagalguy....refrain frm all this
25671
@himanshusood5 said:
anyone wants all CL material including mock tests ( online and paper based ) and T.I.M.E mocks for a bit of money
NO Selling in this thread?
25672
@Dexian said:
sir aapke sol me ek error hai... 56 +55 =111 which is not there.it shud be 54 56 58 59 62........yes i have found a bug in ur sol..... i can sleep well now...
It was a typo .. have edited that .. The last weight would be 54 :)
And I am also a human ..typos can occur :D
But if a mistake of mine gives u good sleep ,it's good that i commited a typo hehehe:p
@himanshusood5 said:
@bodhi_vriksha aint the way to solver it brobest way always is assume the boxes to be a b c d and enow pairs of 2 out of 5 will make ten combosabacadaebcbdbecdcedebasically each box involved in 4 times so wot we get now when we add all the ten weights is4 ( a plus b plus c plus d plus e )divide this by 4 and use equations accordingly to solve ahead

CAT is an exam of time ..it is not about solving the question to entirety .I feel your approach takes a lot of time and mine would take seconds .. so no point solving the entire question when you are provided the options and they make your job simpler :)


Team BV--Pratik Gauri
25673
@bodhi_vriksha no offence but it doesnt .. its done in the mind .. explation mite seem long

algorithm goes like this

combos of 2 out of 5
that means 10 weights
add them

each weight wud obv hve been tken 5 times ..

u get the total weight

subtract the 2 minimum weights frm them and u get the highest weight and then keep going

25674

guys deleted my post

25675
@albiesriram said:
One more geometry ,

AD is the only chord starting at A which is bisected by BC........ ye kya hai...
how do we use this info...

25676
@himanshusood5 said:
@bodhi_vriksha no offence but it doesnt .. its done in the mind .. explation mite seem long algorithm goes like thiscombos of 2 out of 5 that means 10 weights add themeach weight wud obv hve been tken 5 times .. u get the total weight subtract the 2 minimum weights frm them and u get the highest weight and then keep going
See Himanshu ..i have solved this problem using many ways but i found this one the shortest. So posted it for the people to take advantage of it . If you feel your approach is short, go along with it :)

Team BV--Pratik Gauri
25677
@bodhi_vriksha just btw .. wot is team bv ??

25678
@Dexian said:
AD is the only chord starting at A which is bisected by BC........ ye kya hai...how do we use this info...
I know that feel bro./ may be some clue to redraw the picture.
well dont know
25679
@albiesriram said:
One more geometry ,
@bodhi_vriksha sir help us on this.
25680
@jain4444 said:
John has a bag of colored billiard balls which are labeled with the numbers 1,2,3,4,5,6. He reaches into the bag, draws out a ball, records down the number and then places the ball back in the bag. He does this a total of 4 times (hence has 4 numbers). The probability that at least 2 of the numbers are equal is a/b, where a and b are positive, coprime integers. What is the value of a+b?
265?? not at all sure....dead sleepy :/
25681
@jain4444 said:
John has a bag of colored billiard balls which are labeled with the numbers 1,2,3,4,5,6. He reaches into the bag, draws out a ball, records down the number and then places the ball back in the bag. He does this a total of 4 times (hence has 4 numbers). The probability that at least 2 of the numbers are equal is a/b, where a and b are positive, coprime integers. What is the value of a+b?
If you post solution to this .. please tag me. I didn't even get the idea how to attempt these type of questions.
25682
ďťż
25683
@albiesriram said:
60
25684
@albiesriram said:
w=x^24
w=y^40
w=xyz^12
w=x^12*y^12*z^12
w=w^1/2 w^12/40 *z^12
w(1-1/2-3/10)=z^12
w^1/5=z^12
1/5 logw=12
logw=60
25685
@albiesriram said:
log w = 60
OA ?
25686

25687
@jain4444 said:
John has a bag of colored billiard balls which are labeled with the numbers 1,2,3,4,5,6. He reaches into the bag, draws out a ball, records down the number and then places the ball back in the bag. He does this a total of 4 times (hence has 4 numbers). The probability that at least 2 of the numbers are equal is a/b, where a and b are positive, coprime integers. What is the value of a+b?
(6^4-6c4 )/6^4 = 427/432 = 859?