CAT 2007: Quantitative Questions a Day 51 to 100 - The Discussions Quantitative

Please carry the QQAD discussion for the next 50 problems here.
Try getting each and every solution in the very 1st attempt itself. Avoid risky speed.
Just in case you see any mod around, please request him to make this thread sticky.
Good Luck to all :-)
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For: Quant quest'n a day#87
Let x, y, z be prime numbers in the arithmetic progression such that x > y > z. Which among the following is always true?
(a) x z is divisible by 12
(b) x + y is divisible by 8
(c) xz - 1 is divisible by 7
(d) atleast two of the foregoin...
Hi Deepan, many thanks for the consildated doc,
can tell me if there is a similar consolidated doc for 1 to 50 anywhere?
Rock on!
Question(s): (Part A)
An insect starts at vertex A of a certain cube and is trying to reach at vertex B, which is opposite A, in 5 or fewer steps where a step consists travelling along an edge from one vertex to another. The insect will stop as soon as it reaches B. The number of ways in whic...
Frame equations using the given conditions and solve them......u'll get two equal values and the third value as half of the previous two......then take any suitable no.(eg. 100) and get the answer.
Please continue the discussion for the next 33 problems here:)
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Hi Vinit,
For the Part A, Hot did you settle with the numbers 100 200 200 ... I mean was it just luck or was there a bit of the logic used ... I would be happy to understand if there is any logic used.
I am jumping with joy!!:)
@All ... Vineet will open a new thread for QQAD discussion from 101 to 133. This will be the penultimate thread for this season's QQAD. In all around 65 more NLs will be delivered from now, which means 130 questions more. From next week QQAD will be 5 days a week affair. We will stop on 02/11 i.e...
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While attepting QQAD Practice test 3, i found a couple of questions that I could not figure out how to solve,
9) A cone height 2 m and raduis 1 m, Is placed inside a bigger cone of 2 m raduis, such that their axis are common and vertes of smaller cone is at the center of the base of ...
@aarav/vineet-dont you think after getting reqd. sum as 4/3n,we should straightaway mark option "e" as all other options are in range of something but we are getting reqd. sum as exactly 4/3n.
ans a
wrong post.
ans b
assume triangle third angle -> 0
the expression reduces to
2 side^2/side^2 -> 2 hence answer (b)
separate all odd terms and even terms we have
1+ 1/9+ 1/25 ........... + 1/4( 1+ 1/4 +1/9.........)
so S= S/4+ N
3/4S = N
S= 4/3 N
so (e)
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Thanks a ton Deepan
Got It!
Sum Of The Reqd. Series=4/3n
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Questions and answers from 51 to 99..
doc file
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The answer is not C for the changed question. Please be more careful in selecting the right option.
Did you pay heed to the open bracket in option (c)?
The 1st problem got changed.Following is the way one could have thought of for doing the same...
The roots of sinx/x are n*pi,viz +/- pi.+/-2pi and so on.
Hence,sinx/x = (1-x/pi) (1+x/pi) (1-x/2pi) (1+x/2pi) (1-x/3pi) (1+x/3pi)...
Coeff of x^2 here= -(1/pi^2 + 1/4pi^2 + 1/9pi^2 + ......
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Hey aarav...got approach...the ans should be c...good job!!!!!!!!!!