Quant Basics for Zeros in Quant - CAT 2012

MBA CAT 2024
141
solving 3x-4y+2z =0 and 4x-2y-z=0 we get,
11x-8y= 0
11x = 8y
x/y = 8/11

Now again solving 3x-4y+2z =0 and 4x-2y-z=0 we get,
-5x+4z= 0
-5x= -4z
x/z = 4/5

so x:y:z = 8:11:10
Therefore x:z:y = 8:10:11


Hi rocker!

How did u arrive at 11x-8y=0?
142
3x-4y+2z=0 & 4x-2y-z=0
find x:z:y.



we can also use the cross multiplication method here....

3x-4y+2z=0
4x-2y-z=0

write as
3 -4 2 3
4 -2 -1 4

x/(-4*-1)-(2*-2) = y/(2*4)-(3*-1) = z/(3*-2)-(4*-4)

x/8 = y/11 = z/10

therefore x:y:z :: 8:11:10
143
Hi rocker!

How did u arrive at 11x-8y=0?


Originally Posted by HydRocker
solving 3x-4y+2z =0----> A and
4x-2y-z=0-------> B
A+2B gives 11x-8y= 0
11x = 8y
x/y = 8/11
144

----Double post------

145

Hi,

All the Pagals........
Was looking for something like this thread from last 15-20 days
and finally got a thread which is in the nascent stage.......
So will always be here on the same
Hope we will make it count for all of us:cheers:

146
neyati bhanot Says
-12 is added


There is a property about numbers in fraction:

If to a fractional number same number is added to both numerator and denominator then the resultant fraction will always be higher then the original one and as is evident from the problem the fraction has reduced so one can conclude that the number added in a negative one
bu using the same you can rule out some options and can move further
and can solve bu using
(4+x/7+x)= 8/17
cross multiply and solve further
147
neyati bhanot Says
-12 is added


There is a property about numbers in fraction:

If to a fractional number same number is added to both numerator and denominator then the resultant fraction will always be higher then the original one and as is evident from the problem the fraction has reduced so one can conclude that the number added in a negative one
bu using the same you can rule out some options and can move further
and can solve bu using
(4+x/7+x)= 8/17
cross multiply and solve further
148
neyati bhanot Says
-12 is added


There is a property about numbers in fraction:

If to a fractional number same number is added to both numerator and denominator then the resultant fraction will always be higher then the original one and as is evident from the problem the fraction has reduced so one can conclude that the number added in a negative one
bu using the same you can rule out some options and can move further
and can solve bu using
(4+x/7+x)= 8/17
cross multiply and solve further
149

There is a property about numbers in fraction:

If to a fractional number same number is added to both numerator and denominator then the resultant fraction will always be higher then the original one and as is evident from the problem the fraction has reduced so one can conclude that the number added in a negative one
bu using the same you can rule out some options and can move further
and can solve bu using
(4+x/7+x)= 8/17
cross multiply and solve further

150

1. B as a percentage of A is equal to A as a percentage of (A + B). Find B as a percentage of A.

(A) 62%
(B) 73%
(C) 41%
(D) 57%

151

@ HYDROCKER..... Bhai not able to understand it.. Plz tell the answer ASAP......

152
1. B as a percentage of A is equal to A as a percentage of (A + B). Find B as a percentage of A.

(A) 62%
(B) 73%
(C) 41%
(D) 57%


From the question stem, we know B/A = A/(A+B) ..... I

As B is a percent of A, let us assume B = Ax

Then, equation I can be re-written as x = 1/(1+x)

Or x(1 + x) = 1

After this step, trial and error works best. The solution is 62%, answer choice (A) is the correct one.

Alternatively, solving, we get x^2 + x - 1 = 0

Or x = (-1+root 5)/2 or (-1-root 5)/2

= (-1+root5)/2 = 1.24/2= 0.62 = 62%
153

Q 1 An article is sold at a profit of 20% . if both the cost price and the selling price reduced by rs 100 . the profit would be 4 % more find the cost price

Q2 a person sells his table at a profit of 25/2% and the chair at a loss of 25/3% but on the whole he gains rs 25 . on the other hand if he sells the table at a loss of 25/3% and the chair at a profit of 25/2% then he neither gain nor loss
find the cost price
plzz provide me the solutions of these questions m nt able to get d correct ans

Thanks and regards
Deepika

154
Q 1 An article is sold at a profit of 20% . if both the cost price and the selling price reduced by rs 100 . the profit would be 4 % more find the cost price



Hi;
We get 2 Equations. as per the question solving which we get the req. ans.
(s-c)/c = 20/100 ............................(1)
(s-100)-(c-100)=(c-100)(104/100).....(2)

Solve simultaneous eq. to get the ans..


'Q2 a person sells his table at a profit of 25/2% and the chair at a loss of 25/3% but on the whole he gains rs 25 . on the other hand if he sells the table at a loss of 25/3% and the chair at a profit of 25/2% then he neither gain nor loss
find the cost price .'

Let CP be x,y respectively::again 2 simultaneous equations:-
x(1+25/200) + y(1-25/300) - (x+y) =25......(1)
x(1-25/300) + y(1+25/200) = (x+y)............(2)



Regards,
Never Back Down
155
Q 1 An article is sold at a profit of 20% . if both the cost price and the selling price reduced by rs 100 . the profit would be 4 % more find the cost price

Q2 a person sells his table at a profit of 25/2% and the chair at a loss of 25/3% but on the whole he gains rs 25 . on the other hand if he sells the table at a loss of 25/3% and the chair at a profit of 25/2% then he neither gain nor loss
find the cost price
plzz provide me the solutions of these questions m nt able to get d correct ans

Thanks and regards
Deepika

1. Answer = Cost Price is 600 rs

2. answer = cost of table = 360, Cost Of chair = 240

@ Deeps plz let me know if answers are correct.......
and keep posting questions...... Thanks

PS = if my answers are correct . then both the questions can be solve by simple linear equations..

Thanks
ailuroph0bic.......
156

Bhaiyon great job...Chak de CAT-2012..

I'll post questions as well...saare topics kar lenge...



Dis is different...Plz suggest me best buks For quant and di...
Arihant,nishit or Arun Sharma:clap:

157
1. Answer = Cost Price is 600 rs

2. answer = cost of table = 360, Cost Of chair = 240

@ Deeps plz let me know if answers are correct.......
and keep posting questions...... Thanks

PS = if my answers are correct . then both the questions can be solve by simple linear equations..

Thanks
ailuroph0bic.......


Your answers are correct...!!!!!!!!!!!...:cheers:
158
This thread should b more active yaa!!!!!!!!!!!!!!!!!!!!!!!
159

Common PUYS.... Post some Faadu questions..........

160
ailuroph0bic Says
Common PUYS.... Post some Faadu questions..........

Find Last Digit of the given expression->
1!+2!..................324!

Regards,
Never Back Down