[Ankurb]

Originally Posted by MaskedMenace

Find the remainder when 28! is divided by 62 ?


Let 28! mod 31 = P

30! mod 31 = 30

12P mod 31 = 30

12P = 31k + 30

p = (31k + 30)/12

k = 6 => P = 18

so, effective remainder is 18*2 = 36

cannot be 36, plz check once more
It should be 46.

[gomahan]

Originally Posted by santacloud9

hi mr go ,but why did u multiplid it with 8 and how is "24 miss "? plz explain it to me
thnks

multiply 8 times means he is tried same set 8 times

[Ankurb]

Originally Posted by mahi101987

Let [x] denotes the greatest integer that is less than or equal to x, e.g. [3.45] = 3, then [1/3] + [2/3] + [2^2/3] + [2^3/3] +...+ (101 terms) equals


(a) 1/3( 4^50 - 1) - 50
(b) 1/3( 4^51 - 1) - 51
(c) 2/3( 4^50 - 1) - 50
(d) none of the above

option (c)

[MaskedMenace]

Originally Posted by Ankurb

cannot be 36, plz check once more
It should be 46.

Let 28! mod 31 = P

30! mod 31 = 30

2P mod 31 = 30

2P = 31k + 30

p = (31k + 30)/2

k = 0 => P = 15

so, effective remainder is 46

[kumarbe]

I could not understand from the 3 rd step

2P mod 31 = 30 ...

Plz elaborate

[MaskedMenace]

There are 11 books on a shelf. How many ways are there to choose 4 of them so that no two of the chosen books stand next to each other?

(a) 70 (b) 165 (c) 495 (d) none of these

[Ankurb]

Originally Posted by MaskedMenace

Let 28! mod 31 = P

30! mod 31 = 30

2P mod 31 = 30

2P = 31k + 30

p = (31k + 30)/2

k = 0 => P = 15

so, effective remainder is 15*2 = 30

ankur can u post ur method ? i checked it and getting 30 ...

my method is no different from yours.
P = 15, you got it correctly but after that why to multiply it by 2. we didn't divide previously.
31k + 15 = 2g
k = 1
remainder is 46

[MaskedMenace]

Originally Posted by kumarbe

I could not understand from the 3 rd step

2P mod 31 = 30 ...

Plz elaborate

I just wrote 30! mod 31 as 30*29*28! mod 31 = 2p mod 31

[MaskedMenace]

Originally Posted by Ankurb

my method is no different from yours.
P = 15, you got it correctly but after that why to multiply it by 2. we didn't divide previously.
31k + 15 = 2p
k = 1
remainder is 46

But the actual question is 28! mod 62, we divide it by 2 then it becomes 28! mod 31

[Mani_23]

Originally Posted by MaskedMenace

There are 11 books on a shelf. How many ways are there to choose 4 of them so that no two of the chosen books stand next to each other?

(a) 70 (b) 165 (c) 495 (d) none of these

answer is 70..ryte??
its 8c4