Official Quant thread for CAT 2013

@albiesriram said:
This is an olymipiad question which I had done before.
The answe comes out to be 568.
Not for CAT in any way

The cost of 5 pens, 8 erasers, 11 sharpeners is 54. 3 pens, 5 erasers , 7 sharpners is 34. 1pen+1eraser+1sharpener=?. puys, need sm help here....hw to approach such type of probs?

@pinaknagaon said:
The cost of 5 pens, 8 erasers, 11 sharpeners is 54. 3 pens, 5 erasers , 7 sharpners is 34. 1pen+1eraser+1sharpener=?. puys, need sm help here....hw to approach such type of probs?
5P + 8E + 11S = 54 --- (1)
3P + 5E + 7S = 34 ---(2)

(1) - (2)

2P + 3E + 4S = 20 ---(3)

4P + 6E + 8S = 40 --- (4)

(4) - (2)

P + E + S = 6
@ScareCrow28 said:
5P + 8E + 11S = 54 --- (1)3P + 5E + 7S = 34 ---(2)(1) - (2) 2P + 3E + 4S = 20 ---(3)4P + 6E + 8S = 40 --- (4)(4) - (2)P + E + S = 6
hw did u approach it???.... i mean is der any specific method to solve such probs....
@pinaknagaon said:
The cost of 5 pens, 8 erasers, 11 sharpeners is 54. 3 pens, 5 erasers , 7 sharpners is 34. 1pen+1eraser+1sharpener=?. puys, need sm help here....hw to approach such type of probs?
5P + 8E + 11S = 54 --- 1
3P + 5E + 7S = 34 ---2

multiply (1) by 2 and (2) by 3 and subtract

P + E + S = 6

EDITED

@pinaknagaon said:
The cost of 5 pens, 8 erasers, 11 sharpeners is 54. 3 pens, 5 erasers , 7 sharpners is 34. 1pen+1eraser+1sharpener=?. puys, need sm help here....hw to approach such type of probs?
5x + 8y + 11z = 54...i
3x + 5y + 7z = 34...ii

multiply i by 2 and ii by 3,subtract

10x + 16y + 22z = 108
9x + 15y + 21z = 102

x + y + z = 108 - 102 = 6 ?
@pinaknagaon said:
hw did u approach it???.... i mean is der any specific method to solve such probs....
No specific approach brother! 😃 You just have to find it on your own, see @techgeek2050 approach, it's better! :splat: So for these type of questions, you have to see through your own approach
@techgeek2050 said:
5P + 8E + 11S = 54 --- 13P + 5E + 7S = 34 ---2multiply (1) by 8 and (2) by 5 and subtract P + E + S = 6
Oye..ye kaise aya ??
Equation to solve ni hogi directly

@

@ScareCrow28 said:
No specific approach brother! You just have to find it on your own, see @techgeek2050 approach, it's better! So for these type of questions, you have to see through your own approach
so itzz like hit and trial ??
@ScareCrow28 said:
Oye..ye kaise aya ??Equation to solve ni hogi directly
Bhai 2 aur 3 se multiply kia.. ghalti se 8 n 5 likh dia
@pinaknagaon said:
@ so itzz like hit and trial ??
Yes, it has to be hot and trial i am afraid!
@pinaknagaon said:
@ so itzz like hit and trial ??
no need fr hit n trial
suppose u multiply 1 by x and 2 by y

5P + 8E + 11S = 54 --- 1
3P + 5E + 7S = 34 ----2

P + E + S = ?

the coefficeint of P on subtraction will be (5x - 3y) and E will be (8x - 5y)

we need coeff to be 1

so

5x - 3y = 1
8x - 5y = 1

=> x = 2 , y = 3


@techgeek2050 said:
no need fr hit n trialsuppose u multiply 1 by x and 2 by y 5P + 8E + 11S = 54 --- 13P + 5E + 7S = 34 ----2P + E + S = ?the coefficeint of P on subtraction will be (5x - 3y) and E will be (8x - 5y)we need coeff to be 1so 5x - 3y = 18x - 5y = 1=> x = 2 , y = 3
nyc approach... hope it works in odr probs as well... nahi to hit and trial zidabaad!!!
@albiesriram
44=2*2*11
So the only case where we get the product of five integers as 44 is

1*(-1)*2*(-2)*11
Hence , upon adding the above values , we get the sum n =11

@albiesriram said:
44 = 2*2*11 = 1*(-1)*2*(-2)*11
Sum = 11
@albiesriram said:
11
@albiesriram said:
11??

solution..

How many increasing arithmetic progression of three terms can be formed from first 20 perfect squares?

Don't have the OA.

Any approach other than trial and error?