division problem

32008+72008+2008
if divided by 28 what is the reaminder....
ans-1
please tell me how?????

29 Answers

1
Philip Calvert ·

yes tapan that is only what he has written jus think one more step ahead ....

1
Philip Calvert ·

copy pasting my post #13 as it seems to have been lost

"is the answer written as -1 coz i am getting 28"

1
Philip Calvert ·

yes that's wat tapan..

21
tapanmast Vora ·

@philip,
to ans wat u wer asking 4 proof in nishant sir's soln....

2008 = 2001 + 7;
= 29*69 + 7;

{i dunno how did sir get 20??? as 1988 aint div by 29 }
try out by wat i suggested

u'll get da ans.....

21
tapanmast Vora ·

oh shit........

made a fool of myself [9] [4]

yeah yeah........ FINALLY got ur point......

thnx dude.....

1
Philip Calvert ·

29K/3 is an integer from the third line of your very post tapan

21
tapanmast Vora ·

oh k k PHILIP now i got how r u wanting me 2 fashion my thinkin(hopefully)

BUT STILL A DBT REMAINS .... SORRY DUDE 4 HARASSIN U SO MUCH.........

3^29 - 3 = 29k;

3(3^28 - 1 ) = 29k ;

3^28 - 1 = 29K/3 ;

BUT HOW CAN U SAY THAT 29K/3 WILL BE AN INTEGER AS K MAY/MAY NOT B DIVISIBLE BY 3????????????????? [7]

BCOZ V GOTTA PROVE : 3^28 - 1 = 29P

WER P,K ARE INTEGRS

1
Philip Calvert ·

ulta socho bhai agar 3^29 remainder 3 ka chor ta hai to 3 ^ 28 kitnne ka chorega?...

21
tapanmast Vora ·

THEN HOW DID SIR GET, 328≡1 (mod 29) USING ap≡a (mod p)

IF U HAV GOT IT CAN U PLZ POST IT HOW??? [7]

1
Philip Calvert ·

no tapan we can't divide in congruences
i think there is something else to it

but think of what nishant bhaiyya did the other way round...

21
tapanmast Vora ·

@PHILIP PL REPLY TO THIS DBT OF MINNE....

@philip do u mean to say by dividing 3 on both sides u get 328≡1 (mod 29)

12≡4(mod 4)

divide by 4 on both sides....

3≡1(mod 4)

21
tapanmast Vora ·

SIR,
THIS WAS THE METHOD I WAS WORKING WITH..... EQUALLY LOOONG.....

1
Philip Calvert ·

no i bet my method is much more messy than urs
the idea of using fermat's theo like this never ocurred so you can make out how long my method must have been...

but please clarify your step of reducing 2008 to 20

21
tapanmast Vora ·

@philip do u mean to say by dividing 3 on both sides u get 328≡1 (mod 29)

but is dividing on both sides allowd in congruence modulo?? [7]

Nishant Sir has doe so has to be rite but i had a doubt,
c

12≡4(mod 4)

divide by 4 on both sides....

3≡1(mod 4)
[7] [7]

62
Lokesh Verma ·

yes philip they are the same..

do you have a simpler method.. I think the method by me is a bit messy for my own liking :(

1
aditya ·

sorry it's 29 not 28.....

21
tapanmast Vora ·

ap≡a (mod p)

then how does this follow?? [7]

328≡1 (mod 29) (fermat's theorem.. not in syllabus)

shud it not b sumthing like : 329 ≡ 3(mod 29) ????

1
Philip Calvert ·

bhaiyya i can't get that step

3^2008-1988+7^2008-1988+2008-1988 [7][7]

1
Philip Calvert ·

is the answer written as -1 coz i am getting 28

62
Lokesh Verma ·

no this is not in IIT JEE syllabus.

it is a theorem which says that

ap≡a (mod p)

But this is not in IIT JEE syllaubs

What is expected from you in an IIT JEE exam is that you are able to solve the problems that need binomial theorem.

21
tapanmast Vora ·

OH K....

ya got my mistake....

THank You Sir!!!! [1]

11
Subash ·

328≡1 (mod 29)

please explain this in a bit more detailed fashion

and are such type of expected to appear in jee or aieee

62
Lokesh Verma ·

32008+72008+2008
if divided by 29 what is the reaminder....

328≡1 (mod 29) (fermat's theorem.. not in syllabus)
thus 31988≡1 (mod 29)

and similarly
728≡1 (mod 29)
71988≡1 (mod 29)

Now you can take it from here..

32008-1988+72008-1988+2008-1988 (mistake pointed by tapan )
if divided by 29 what is the reaminder....

=320+720+2008
if divided by 29 what is the reaminder....

21
tapanmast Vora ·

SUM1 TRY THIS YAAR!!!

THIS TYPE IS A FREQUENT FEATURE.....

21
tapanmast Vora ·

CAN SUM1 TRY THIS UN???

21
tapanmast Vora ·

YEAH!!!!!!!!

me 2 gettin ans 10 after dividing by 29 [7]

but unfortunately the ans raeds 1 [2]

1
Philip Calvert ·

so ans should be 10 [7][7]
for division by 28 not 29

1
Philip Calvert ·

7^2008 % 28 = 21 not 3

11
rkrish ·

32008 = 3*(32007) = 3*(27669) = 3*((28-1)669) = 28m - 3

So 32008 / 28 gives remainder = 25

72007 = (8-1)2007 = 4n - 1

So 72008 / 28 gives remainder = 3

So 32008 + 72008 / 28 gives no remainder

502 = (497 + 5) = 7k + 5

So 2008 / 28 gives remainder = 5

Hence [ 32008 + 72008 + 2008 ] / 28 gives remainder = 5

I don't understand how the ans given is 1 [7][7][7][7]

Somebody correct me if I'm wrong!!

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