Official Quant thread for CAT 2013

MBA CAT 2024
28465
@albiesriram said:
for second is it r/2R
THIS IS RATIO OF AREAS

28466
guys, couldnt find enough challenging questions on any mba forum, so went ahead and started with the olympiad papers. For people seeking greener pastures, and aiming to challenge themselves, i suggest you try them out here: http://olympiads.hbcse.tifr.res.in/subjects/mathematics/previous-question-papers-and-solutions.

Am able to solve only 2/5 problems in a paper, but for math addicts, this is the ultimate haven! Dont give up till you solve 5/5 in all!
28467
@albiesriram said:
2. r/R?
28468
@albiesriram said:
1/2, 1/3...did some hard work here...anyone with a short method?

r/R ....take equilateral triangle
28469
@albiesriram said:
FOR 1ST IT WILL BE C 1/2 AND 1/3
28470
@albiesriram said:
FOR SECOND 1 I FIRST POSTED RATIO OF AREAS :p
PERIMETERS WILL BE r/R
28471
@RDN said:
1/2, 1/3...did some hard work here...anyone with a short method?r/R ....take equilateral triangle
p= n/2(2a+(n-1)d)/n/2(2(a+nd)+(n-1)d)
p= 2a+(n-1)d/2a+(3n-1)d
divide numerator and denominator by d
let a/d=x
p=2x+n-1/2x+3n-1
now use options
28472
@vbhvgupta said:
if the roots of the eqn a(b-c)X^2 + b(c-a)X + c(a-b) = 0 are equal, then a,b ,c are inAPHPGP
GP saar ??
28473

OA for previous problems is C n C



28474
@DeAdLy said:
GP saar ??
____/\____
28475
@vbhvgupta said:
No of roots of the eqn x - 2/(x-1) = 1 - 2/(x-1) is
0 hai kya ??
28476
@albiesriram said:
OA for previous problems is C n C
-5050...substitute x-2, then find product of roots

imaginary....p,q,r =3,4,6....delta is -ve
28477
@albiesriram said:
OA for previous problems is C n C
for 1
-5050
28478
@albiesriram said:
OA for previous problems is C n C
for second imaginary
28479
@albiesriram said:
OA for previous problems is C n C
1. r1 + r2 + r3 = 2
r1r2 + r2r3 + r3r1 = 4
r1r2r3 = 4

(r1 + 2)(r2 + 2)(r3 + 2) = r1r2r3 + 2(r1r2 + r2r3 + r3r1) + 4(r1 + r2 + r3) + 8
----> -5074 + 8*3 = -5050 ?
28480
28481
@vbhvgupta said:
Q


let alpha be A and beta be B
So A+B = -b/a
AB = c/a
Now sum of new roots = A+1/B+B+1/A = -b(a+c)/ac
Product of new roots = (c/a+a/c+2)
New equation = x^2 - sumX + product
It comes optin (c)
28482

the average marks of 3 students x,y,z is 48. Another student k joins the group the new average becomes 44. If another student p joins who has 3 more marks than k , the average of y,z,k,p becomes 43. How many marks x got in exam ??


1.43
2.35
3.39
4.47
28483
@vbhvgupta said:
Q
it will be c ?
28484
@DeAdLy said:
the average marks of 3 students x,y,z is 48. Another student k joins the group the new average becomes 44. If another student p joins who has 3 more marks than k , the average of y,z,k,p becomes 43. How many marks x got in exam ??1.43 2.353.394.47
39 ?