Official Quant thread for CAT 2013

MBA CAT 2024
28108
@IIM-A2013 said:
if one root of the equation (I-m)x^2+Ix+1=0 is double of the other and is real find the greatest value of m.a 9/8 b 8/7 c 8/6 d 7/5
a, 2a

3a = I/(m-I)
2a^2 = 1/(I-m)

=> 2(I-m) = 9(m-I)^2 / I^2
=> 2(I-m)I^2 = 9(m-I)^2
=> 2I^2 = 9(I-m)

2I^2 -9I + 9m = 0
81 - 72m >= 0

m ..
28109
@pavimai said:
Meena and neena starts simultaneously fom Atowards B .when M has covered 27km N doubles her speed & 6 hrs later she overtakes Meena .What is neena s original speed? Meena speed is 45 km/hr
Ans ??
28110
@abhishek.2011 said:
4c1*10*9*8*7/40c4
Actually, Though the answer will any way be none of these, But I think we cant use 40C4 here as the sample space. The cards are being taken one by one, and hence arrangement is important. hence we should use 40*39*38*37 rather. isnt it? or am i wrong?
28111
@albiesriram said:
8c2 - 8=20 diagnols
20-4=16 ??
28112
@albiesriram said:
Actually, Though the answer will any way be none of these, But I think we cant use 40C4 here as the sample space. The cards are being taken one by one, and hence arrangement is important. hence we should use 40*39*38*37 rather. isnt it? or am i wrong?
ya if u r using 40c4 in the denominator then numerator has to be 4c1*10c4
but as one by one cards are drawn it should be 4c1*10*9*8*7/40*39*38*37
28113
@Dexian said:
A) 12
Nope..
OA:-

28114



28115
@IIM-A2013 said:
if one root of the equation (I-m)x^2+Ix+1=0 is double of the other and is real find the greatest value of m.a 9/8 b 8/7 c 8/6 d 7/5
is it 9/8
m maximum at i=9/4
28116
@pavimai said:
Meena and neena starts simultaneously fom Atowards B .when M has covered 27km N doubles her speed & 6 hrs later she overtakes Meena .What is neena s original speed? Meena speed is 45 km/hr
is it 23.6 ??
28117
@albiesriram said:
8c1*6c1*10c1=480 ??
28118
@albiesriram said:
480
28119
28120
@abhishek.2011 said:
is it 23.6 ??
can you share your approach
28121
@albiesriram said:
8c1*6c1*10c1 = 480 ?
28122
@albiesriram said:
140
28123
@pavimai said:
can you share your approach
You can check my post, if you have time!
28124
@albiesriram
c)140
28125
@albiesriram said:
is it 2r^2/3
1/2*4r*r=1/2*3r*x
x=4r/3
area of the traingle 1/2*r*4r/3 = 2r^2/3
28126
@albiesriram said:
it will be 140
28127
@albiesriram said:
140 ?

only blue = 60 - ((15 - 5) + 5 + (20 - 5)) = 30
only red = 60 - ((15 - 5) + 5 + (25 - 5)) = 25
only black = 75 - ((25 - 5) + 5 + (20 - 5)) = 35
so I + II + III = 30 + 25 + 35 + (15 - 5) + (25 - 5) + (20 - 5) + 5 = 140