New Problems

Hi if u can solve this problems thn plz come up with soln. & submit the way to approach....

Q1. 1000!=(100!)^k - P Where P is a prime number & both P,k are integers. Find the maximum value of k.

(a)105, (b)106, (c)104, (d)102,(e)None.

Q2.What is the sum of the sum of  the digits of 55!.

(a)36, (b)25, (c)9, (d)5.

Q3.Find the remainder of 40!/83.

(a)45,(b)81,(c)65,(d)1.

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As per Wilson's Theorem,If
As per Wilson's Theorem,
If P is a prime number then
 
(p-1) % p = (p-1) or -1
 
So 82! % 83 = 82
 
=> [ 40! x 41 x 42 . . . .   x 82] %83 = 82
 
=> [ 40! x  (83 - 42) x (83 – 41) . . . .   x (83 – 1)] % 83  = 82
 
=> [ 40! x  (- 42) x ( – 41) . . . .   x ( – 1)] % 83  = 82
 
=> [ 40! x  42 x  41 x 40! ] % 83  = 82
 
=> [ 40! x  62 x  40! ] % 83  = 82
 
=> [ (40!)2 x  62 ] % 83  = 82
 
Now follow trial and error to find out what is the reminder of (40!)2 when divided by 83.
 
Let this be 2 then 62 x 2 = 124 and 124 % 83 = 41 , so it doesn’t satisfy our condition.
Let this be 3 then 62 x 3 = 186 and 186 % 83 = 20 , so it doesn’t satisfy our condition.
Let this be 4 then 62 x 4 = 248 and 248 % 83 = 82 and it satisfy our condition.
 
So  (40!)2 % 83  = 4
=> (40!) % 83  =  +/- 2
 
Thus the answer is 83 – 2 = 81
 

Why it should not be 2 . . . .take it as an assignment

 

thank u

for that wilson's thorem

Question 2

Q2.What is the sum of the sum of  the digits of 55!.

(a)36, (b)25, (c)9, (d)5.

ANS:

I think its 9

all the numbers ≥ 6 gives 9

i.e Sum of(Sum of(digits of n!)) = 9 where n ≥ 6

@Anita1

 I think at the primitive stage of ths problm as u hv taken (p-1)....So at the last time u should take (p-2) instead of takin only -2....

Thankin you,

Dipanjan

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Can any 1 solv the 1st

Can any 1 solv the 1st problm wth explanation....l

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@Searchin

Thankz 4 givin this Funda

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10000!/100!   let assume a

10000!/100!   let assume a small no. 100!/10!  1!  to  10! will be divided once by denominator   now from (11! to 20!) /10! will give in numerator 2*2 and some prime no similerly from 20! to 30! it will give 3 * 3 and some prime no, so upto 100! it will be devided by 10 times by 10!

now in numerator 1*1*2*2*3*3.............10*10 this will be devided by 2 times more by 10! so answer will be 12

so the original que answer is 102

That's correct and reason is

That's correct and reason is (sum of digits (sum of digits(n!)))

of any number >= six is divisible by 9 as well.

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