Official Quant thread for CAT 2013

@techgeek2050 said:
sir, by now you would have saved millions of trees from being felled.
Making up for past sins I guess......I'm an Aero engineer, and you know what they say: "when the weight of the paperwork equals the weight of the plane, then and only then will the plane fly..."

ObQuant: If a dozen oranges and 16 apples cost rupees 128 while 16 oranges and 5 apples cost rupees 89, what will be the cost of a dozen apples and 9 oranges? Do orally if possible!

regards
scrabbler

@scrabbler said:
Making up for past sins I guess......I'm an Aero engineer, and you know what they say: "when the weight of the paperwork equals the weight of the plane, then and only then will the plane fly..."ObQuant: If a dozen oranges and 16 apples cost rupees 128 while 16 oranges and 5 apples cost rupees 89, what will be the cost of a dozen apples and 9 oranges? Do orally if possible!regardsscrabbler
orally??

not my cup of tea. we mortals use pen and paper.


@techgeek2050 said:
orally?? not my cup of tea. we mortals use pen and paper.
Which is the point I am trying to make. Which is the habit I am trying to break.

The point is, when you write an equation you become a slave to it till it is solved. But if you first think and then write, often enough you find that the writing has become unnecessary...try this one orally, I say again, and you might be surprised. Pleasantly.

regards
scrabbler

@scrabbler said:
Making up for past sins I guess......I'm an Aero engineer, and you know what they say: "when the weight of the paperwork equals the weight of the plane, then and only then will the plane fly..."ObQuant: If a dozen oranges and 16 apples cost rupees 128 while 16 oranges and 5 apples cost rupees 89, what will be the cost of a dozen apples and 9 oranges? Do orally if possible!regardsscrabbler
96
@royy said:
96
Explain, especially if done orally :)

regards
scrabbler

@scrabbler said:
Explain, especially if done orally regardsscrabbler
sir couldn't solve orally ...dont know where to start from but completely agree with u on the slave thing .would try surely
@royy said:
sir couldn't solve orally ...dont know where to start from but completely agree with u on the slave thing .would try surely
So share your approach anyway...

regards
scrabbler

@scrabbler maine orally try karne ki try ki..16 oranges + 5 apples costing 89..so units digits both coulb 0+9 or 4 +5 ..so only 1 sol
and ofcourse 12apples+9oranges=96
@scrabbler said:
So share your approach anyway...regardsscrabbler
take 2nd eq 16x + 5y=89

only one value will satisfy x=4 and y=5 put in required eq 9x + 12y =96

x and y r oranges and apples

PS: this was not done orally

12 O +16 A=128............1

16 O +5 A =89..............2
mul 1 by 16 and 2 by 12
we get A=5
and O=4
so 12A+9O=12x5+9x4=96

@venomizer said:
@scrabbler maine orally try karne ki try ki..16 oranges + 5 apples costing 89..so units digits both coulb 0+9 or 4 +5 ..so only 1 sol
Good hai...not the approach I was looking for though.

regards
scrabbler

@scrabbler said:
Explain, especially if done orally regardsscrabbler
since it's 89, the
16o + 5a = 89

this is possible only in one way --> 64 + 25

so o = 64/16 = 4
and a = 25/5 = 5

am i right?

@venomizer said:
@scrabbler maine orally try karne ki try ki..16 oranges + 5 apples costing 89..so units digits both coulb 0+9 or 4 +5 ..so only 1 sol
@amresh_maverick said:
take 2nd eq 16x + 5y=89only one value will satisfy x=4 and y=5 put in required eq 9x + 12y =96x and y r oranges and applesPS: this was not done orally
@royy said:
12 O +16 A=128............116 O +5 A =89..............2mul 1 by 16 and 2 by 12we get A=5and O=4so 12A+9O=12x5+9x4=96
@techgeek2050

The problem is, all of us are making one error (if I may call it that); we are assuming we need to SOLVE the problem.

By solve I mean, find the cost of an apple or of an orange. Or of O and A, or x and y as the case may be. And that is what happens when we write equations; we tend to get involved with them.

But when trying to solve orally, one key aspect to keep in mind is "what, precisely, do we need to find?" and in this case that is not O or A but 9O + 12A. @royy , look again at your equations...?

regards
scrabbler

@scrabbler atak gyi hai gaadi...nhi aa rha rha..9o+12a kaise...but trying to ...anyways exam ke presure mein nhi hota aisa..pen chal jata hai
@venomizer said:
@scrabbler atak gyi hai gaadi...nhi aa rha rha..9o+12a kaise...but trying to ...anyways exam ke presure mein nhi hota aisa..pen chal jata hai
12 O +16 A=128

You want 9O + 12 A...zara soch!

regards
scrabbler

@scrabbler got it..*3/4
I have just started to prepare for CAT 2013.I heard that topics to be studied in quants are:
* Geometry, (Lines, angles, Triangles, Spheres, Rectangles, Cube, Cone etc)
* Ratios and Proportion, Percentages, In-equations
* Quadratic and linear equations
* Algebra
* Profit & Loss
* Averages, Percentages, Partnership
* Time-Speed-Distance, Work and time
* Number system: HCF, LCM, Geometric Progression, Arithmetic progression, Arithmetic mean, Geometric mean , Harmonic mean, Median, Mode, Number Base System, BODMAS
* Mensuration, Allegation & Mixtures, Work, Pipes and Cisterns
* Simple Interest & Compound Interest
* Set Theory, Venn Diagram
* Installment Payments, Partnership, Clocks
* Probability, Permutations & Combinations

kindly correct me if i need to add or remove any topics.
if some one knows the detailed topicas to cover in quants. please let me know.

side of the largest triangle that can be inserted in hexagon of side 1 cm.?

@scrabbler scrabbler sir, after meeting hearing you out at, i started doing all my questions orally, and discovered that there is absolutely no need for any quant question to be written down, dunno why i didnt do the samw in cat, would have saved tons of time...
@The_Loser said:
side of the largest triangle that can be inserted in hexagon of side 1 cm.?
root 3?