CAT 2008: Quantitative Questions a Day 1 to 50 - The discussions

[abhilash108]

Originally Posted by Aarav

Welcome back to QQAD the answer is correct.

So does everyone agree with 5/8 as solution????
Then I have a small doubt......
the question says: "If x + y ≥ k.(a+b) for all a and b, then k = "...

I stress on "for all a and b".
So there will be a condition where a=b.
In that case, it becomes a square.
Can we say that k=5/8 even in that condition......?

[abhilash108]

Originally Posted by imj0ker

The question was at max, how many students can fail in all 4 subjects. So that is why I said, that since 60 have already passed in DI, so we can not have more than 40 ppl failing in all 4.

got my mistake....thnx

[dewan_iitr]

x=a2/8b + b/2
y= b2/8a + a/2

x+y = (a+b)/2 + (a3+b3)/8ab
= (a+b) [a2 +b2+ 3ab]/8ab

AM >= GM
a2+b2>= 2ab

x+y >= (a+b) [5/8]

k=5/8
Ans (2)

[swathitha]

hi all,

I have joined dis group newly. It seems to be very useful...
i ve subscribed for tat quanti quest. I got only 2day's ques thro mail.
Could anybody plz mail me the 1 to 25 ques with the solu...
Thanks in advance!!!

[cyrusg]

with respect to the question 23, i am not able to understand the solution given by the PG Team. Can anybody exlain me the ans for this ques in a simpler/alternate manner ...


Thanks in advance.

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Quantitative Question # 023
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ABCD is a square, point E is inside triangle ACD and point F is inside triangle ACB. < EAF = <ECF = 45˚. If DE = 3, and BF = 4, then EF equals

(1) 5 (2) 2√3 (3) 7/2 (4) 24/7 (5) none of these

[cyrusg]

with respect to the question 23, i am not able to understand the solution given by the PG Team. Can anybody exlain me the ans for this ques in a simpler/alternate manner ...


Thanks in advance.

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Quantitative Question # 023
------------------------------------------------------

ABCD is a square, point E is inside triangle ACD and point F is inside triangle ACB. < EAF = <ECF = 45˚. If DE = 3, and BF = 4, then EF equals

(1) 5 (2) 2√3 (3) 7/2 (4) 24/7 (5) none of these



Sorry for the duplicate post .. is there no way to delete the duplicate post ... :???

[Aarav]

Originally Posted by cyrusg

with respect to the question 23, i am not able to understand the solution given by the PG Team. Can anybody exlain me the ans for this ques in a simpler/alternate manner ...

Thanks in advance.

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Quantitative Question # 023
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ABCD is a square, point E is inside triangle ACD and point F is inside triangle ACB. < EAF = <ECF = 45˚. If DE = 3, and BF = 4, then EF equals

(1) 5 (2) 2√3 (3) 7/2 (4) 24/7 (5) none of these

Sir, the coordinate solution was given just to make the answer look much simpler. It can't get better than this [at least to our capability].

[smartie]

Aarav, although I have understood the right approach I m nt able to make out where I went wrong..
my approach was :

let the centre of the circle passing thru A and B and touching CD be O.
Then OA=OB=OP=x (P is a point on the circle where CD touches it.Then OP || BC)

Extend OP to intersect AB at R.
Let <AOR= C

Now,
C>=0
or, cos C <=1
or, x *cos C<= x
or, x+x*cosC <= 2x
or, b<= 2x ......(1)

Similarly, a<=2y ........(2)

Adding (1) and(2)

( a+b) <=2(x+y)
then,
(x+y)>= 1/2(a+b)
So k=1/2

So my answer= (4)1/2

Please tell me what is wrong in this process or is it completely wrong?

[vaibhav2cool]

wrong post

[implex]

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Quantitative Question # 027
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Vineet has Rs 600 with him. Each day he buys either beer for Rs 100 or vodka for Rs 200 or whisky for Rs 200. In how many ways can Vineet spend all his money?

(1) 20 (2) 24 (3) 30 (4) 32 (5) none of these

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