Official Quant thread for CAT 2013

MBA CAT 2024
22667
@iLoveTorres said:
bhai idhar 81 ke baad hi 61 aata hai na.. kabhi kabhi oral examm mmein bhi fail ho sakte hai
Kaise? 81 x 21 = 01...21 ke powers dekh rahe hai bhai 81 ke nahin...

regards
scrabbler
22668
@DeAdLy said:
27??
its 37
22669
@rkshtsurana said:
Q. (21) ^ 21^21^21^21......(21 times) remainder by 25 ?P.S - After a long time posting here, Feel so good here..so a question from my side
21 ?
22670
@scrabbler said:
Kaise? 81 x 21 = 01...21 ke powers dekh rahe hai bhai 81 ke nahin...regardsscrabbler
aaj mujhe so jana chahiye.. pata nahi dimag kis angle se soch raha hai...

Gunite Puys :(
22671
Q. Determine F(2010) if for all real x and y , F(x)*F(y) - F(xy) = x+ y ďťż
22672
@scrabbler As usual you came up with the best mehtod..
22673
@viewpt said:
its 37
my god m dozing n doing typos.
..time to leave
...rest will solve in ofc 2moro..
u ppl carry on..
22674
@rkshtsurana said:
Q. Determine F(2010) if for all real x and y , F(x)*F(y) - F(xy) = x+ y
-2625?
22675
@iLoveTorres said:
-2625?
nhi bhai..n plz ans daalo toh approach bhi daala kro..so that ppl also know wrong approaches..it equally imp to know a wrong approach with the right one
22676
@viewpt said:
Q:R= x= 73^79 div 100 find R?
37 ?

73^79 mod 100 = 73^40k mod 100 = 1
73^39 mod 100 = (73)*(73^2)^19 mod 100 = 17*(41^2)^9 mod 100 = 17*41*(81)^4 mod 100 = 97*61*61 mod 100 = 37
22677
@rkshtsurana said:
Q. Determine F(2010) if for all real x and y , F(x)*F(y) - F(xy) = x+ y
2011?

F(x) * F(y) = F(xy) + x + y

Trial and error gave me F(x) = x+1 satisfies as (x+1)(y+1) = (xy +1) + x + y.

So F(2010) = 2010 +1 = 2011?

regards
scrabbler
22678
@scrabbler said:
2011?F(x) * F(y) = F(xy) + x + yTrial and error gave me F(x) = x+1 satisfies as (x+1)(y+1) = (xy +1) + x + y.So F(2010) = 2010 +1 = 2011?regardsscrabbler
kaise achieve kara ye trial and error..??
22679
@rkshtsurana said:
Q. Determine F(2010) if for all real x and y , F(x)*F(y) - F(xy) = x+ y
2011?
agar answer correct hai toh approach daalta hoon.. cos i may be doing some blunder.. if some1 sees the blunder he may also imbibe it which i am totally against
22680
@Logrhythm said:
kaise achieve kara ye trial and error..??
Tried to think what would give me an x and a y left over in multiplying...2nd try pe aa gaya...thoda luck to tha 😃 But have to chance that na...

regards
scrabbler
22681
@iLoveTorres go on man :)

@scrabbler awesome..trial n error was difficult yaar fir bhi u did :)
22682
@scrabbler said:
Tried to think what would give me an x and a y left over in multiplying...2nd try pe aa gaya...thoda luck to tha But have to chance that na...regardsscrabbler
i basically found the prime factors of 2010 which are 67*3*5*2
so F(67)*F(30) - F(2010) = 97
F(67)*F(1)-F(67) = 68 ---> F(67)[F(1)-1]=68 so F(1) can be 69 and F(67) = 1 or F(67)=68 which gives F(1)=2
ab yaha se F(2) ke liye sirf second case mein integer solution aa raha hai so F(2)=3 similarly F(2010)=2011
22683
@iLoveTorres said:
i basically found the prime factors of 2010 which are 67*3*5*2so F(67)*F(30) - F(2010) = 97F(67)*F(1)-F(67) = 68 ---> F(67)[F(1)-1]=68 so F(1) can be 69 and F(67) = 1 or F(67)=68 which gives F(1)=2ab yaha se F(2) ke liye sirf second case mein integer solution aa raha hai so F(2)=3 similarly F(2010)=2011

torres scores, finally 😛
22684
@rkshtsurana said:
Q. Determine F(2010) if for all real x and y , F(x)*F(y) - F(xy) = x+ y
Check dis out
let x = y = 0
F(0)F(0) - f(0) = 0
f(0) [ f(0) - 1 ] = 0
so f(0) = 0 or 1
so now

x = 0 and y = 2010
f(0)f(2010) - f(0) = 2010
f(0) [ f(2010) - 1] = 2010
now f(0) cant be 0 bcz otherwise RHS will have to zero
so f(0) = 1
f(2010) = 2010 + 1 = 2011
22685
@Logrhythm said:
torres scores, finally
but not until @scrabbler assisted :)
22686
@iLoveTorres said:
but not until @scrabbler assisted
To kya...football MBA is about teamwork isn't it?

regards
scrabbler