Number System - Questions & Discussions

can someone start a thread for approach concept...
i mean how to approach a problem and what should we think when we approach a particular number system problem...because thatts the most important thing i suppose...its an urgent necessity as it will make our roots go strong and we can tackle any problem?

plzzz help me......my QA sux........hav always been terrified by QA......... number system particularly................plzz tell me which topics to start with in number systems...
im afraid QA will play spoil sport for me in CAT 2011.


Two of the best QA Threads:
1) http://www.pagalguy.com/discussions/cat-2010concepts-fundas-and-tips-to-crack-quants-section-25055747
2) http://www.pagalguy.com/discussions/official-quant-thread-for-cat-2011-part-1-25060879

hi.......
i m getting stuck in this remainder problem..pls show me where i m wrong...

50^51^52 is divided by 11 :what'll be the remainder?

my approach:
(50^51)^50*(50^51)^2/11 ->(50^51)^2/11 (using FERMAT'S)
->(50^102)/11 ->50^2/11 ->6^2/11 ->remainder 3............m i wrong?answer given is 6!!!!!!

I think you took 50^51^52 as (50^51)^52 but it is actually (50)^51^52
I mean 2^3^4=2^81 and not 8^4 that is the problem with the solution.
Here,Euler will come handy .
E(11)=10
51^52=(50+1)^52 so it is in the form 10n+1
Hence 50^(10n+1) mod 11 =50 mod 11=6 (answer)
Check the quoted post above of your post for Euler theorem !

oh ya! i got it now...thank u..

Found this problem in a previous post,can anyone pls elaborate the method?

1.FIND the Remainder of 5555......93times divided by 98

option-2

give me a detail solution pls....
how is the remainder is 1 when 39! is divided by 41?

give me a detail solution pls....
how is the remainder is 1 when 39! is divided by 41?


there is one theorm called "wilson's theorm"

Acc to which

If P is a prime no , then the reminder when (p-1)! is divided by P is (p-1)

so when (41-1)! divided by 41 , we get answer as 40
now 40! can be written as 40*39!

so (40*39!)/41 we get reminder as 40
transport the 40 to RHS..and we get answer as 1

PS: if there is a way to solve it with out this theorm, kindly post it here
hi.......
i m getting stuck in this remainder problem..pls show me where i m wrong...

50^51^52 is divided by 11 :what'll be the remainder?

my approach:
(50^51)^50*(50^51)^2/11 ->(50^51)^2/11 (using FERMAT'S)
->(50^102)/11 ->50^2/11 ->6^2/11 ->remainder 3............m i wrong?answer given is 6!!!!!!

when u divide 50 by 11 u can write remainder -5, because it is 5 less than next multiple of 11
similarly for 51 = -4 , for 52 it is = -3
now 50*51*52= -5*-4*-3= -60
on dividing by eleven remainder = -5, that means 11-5= 6
:cheerio:
when u divide 50 by 11 u can write remainder -5, because it is 5 less than next multiple of 11
similarly for 51 = -4 , for 52 it is = -3
now 50*51*52= -5*-4*-3= -60
on dividing by eleven remainder = -5, that means 11-5= 6
:cheerio:

how can u do 50*51*52?:shock:
Found this problem in a previous post,can anyone pls elaborate the method?

1.FIND the Remainder of 5555......93times divided by 98


We know that Euler number for 98 is 42. Hence we can say that a number if written 42 times or 84 times will be divisible by 98.

=> 5555......93times = 555...9 times (mod 98 )
= 5*10^8 + 55(10^6 + 10^4 + 10^2 + 1) (mod 98 )

we know that 100 = 2 (mod 98 )

=> 5555......93times = 5*2^4 + 55(8 + 4 + 2 + 1) (mod 98 )= 905 (mod 98 )
= 23 (mod 98 )
=> 5555......93times = 555...9 times (mod 98 ) :drinking::drinking:
i dint get it .. euler applies to the exponent of a no. in the form b^n ..
but can we use this to no. of digits ??

=> 5555......93times = 555...9 times (mod 98 ) :drinking::drinking:
i dint get it .. euler applies to the exponent of a no. in the form b^n ..
but can we use this to no. of digits ??


Actually its an extension of the Euler's theorem.

Suppose we have number N having digit 'a' written 'k' times, where k is Euler's number of 'n'. So, when N is divided by n, reminder will be 1. (Note, n should be coprime to 3 and 10)

Proof:-
N = aaa...a (k times) = (a/9)(10^k - 1)

Now, since 10 and n are coprime, we can say that (10^k - 1) is divisible by n. Now since n and 9 are also coprime, we can say that

(a/9)(10^k - 1) will be divisible by n

So, actually I made a mistake because 98 and 10 are not coprime. So, we need to break 98 inot 2 and 49.
So, clearly using the previous method, we can say
5555...5 (93 times) = 555...9 times (mod 49)
= 5*10^8 + 55(10^6 + 10^4 + 10^2 + 1) (mod 49)
= 5*16 + 55*(8 + 4 + 2 + 1) (mod 49)
= 905 (mod 49)
= 23 (mod 49)

Also, 5555..5 (93 times) = 1(mod 2)

=> 5555...5 (93 times) = 23 (mod 98 )

Hello people,

I'm giving AIEEE and IIT-JEE would any one tell me that which books i have to refer... and also want to know books for MH-CET plzz!!!!!

Hello people,

I'm giving AIEEE and IIT-JEE would any one tell me that which books i have to refer... and also want to know books for MH-CET plzz!!!!!

Hello people,

I'm giving AIEEE and IIT-JEE would any one tell me that which books i have to refer... and also want to know books for MH-CET plzz!!!!!

Hello people,

I'm giving AIEEE and IIT-JEE would any one tell me that which books i have to refer... and also want to know books for MH-CET plzz!!!!!


First of all you are completely on different thread. Do a search before you post.

Pretty old theead, bit I guess will answer the your questions:
1) http://www.pagalguy.com/discussions/aieee-2010-exam-preparation-solutions-25053112
2) http://www.pagalguy.com/discussions/some-help-with-iit-tuitions-to-join-or-not-to-join-25039528

And I didn't understand the connection between IITJEE/AIEEE(Engineering entrance exams) and MAHCET (MBA entrance exams):lookround:.

For MAH CET, refer some basic coaching materials. The exam is more of a speed test than anything else. This year, it had some good questions though.

1) Cracking Maharashtra CET 2011 | PaGaLGuY.com - India's biggest website for MBA in India, International MBA, CAT, XAT, SNAP, MAT

Hope it helps.

Hey guys,


Anyone can please help me with this question..

p=1!+2*2!+3*3!+.....10*10! what is the remainder when p+2 is divided by 11

Hey guys,


Anyone can please help me with this question..

p=1!+2*2!+3*3!+.....10*10! what is the remainder when p+2 is divided by 11


If we take nth term, the nth term is n! * n = n! * (n+1-1) = n! * (n+1) - n! = (n+1)! - n!

hence if we see p = 2! - 1! + 3! - 2! + .....+ 11! - 10! = 11!- 1!

p+2 = 11! + 1

if we divide 11! + 1 by 11, the remainder would be +1.

P.S. Last year one of the AIMCAT, this question was asked.
Hey guys,


Anyone can please help me with this question..

p=1!+2*2!+3*3!+.....10*10! what is the remainder when p+2 is divided by 11


We can also try this

take value of n=2

so
p=1!+2.2!
p=5
add 2 thus p+2=7
now divide p by n+1 ie 7/3 remainder is 1

to verify we can take n=3 and divide p+2/n+1 remainder will again be 1

thus we can say that Remainder will be one in any case
We can also try this

take value of n=2

so
p=1!+2.2!
p=5
add 2 thus p+2=7
now divide p by n+1 ie 7/3 remainder is 1

to verify we can take n=3 and divide p+2/n+1 remainder will again be 1

thus we can say that Remainder will be one in any case

Add and subtract 10!
1*1! + 2*2!..................11*10!-10!
now 10!= 10*9!
1*1! + 2*2!..................9*9!-10*9!+ 11*10!
1*1! + 2*2!.................8*8!-9*8!+ 11*10!
continue this process
ultimately you will reach
P =-1 + 11*10!
P+2=1+11*10!
therefore remainder is 1
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deepak_pgi Says
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