Official Quant thread for CAT 2013

[(1!)^(1!) + (2!)^(2!) + (3!)^(3!) + ............ + (1000!)^(1000!)] / [2^3 X 5^1].

Find the Remainder.

@The_Loser said:
in hw many ways alphabet of letter be arranged so that dre are 7 letters bw a & b.
26^7*2?
@viewpt said:
26^3*2?
bhai kya kiya hai ye?
@sunnychopra89 said:
[(1!)^(1!) + (2!)^(2!) + (3!)^(3!) + ............ + (1000!)^(1000!)] / [2^3 X 5^1].Find the Remainder.
Use CRT

Let Nr=X
then Xmod8=5

also, Xmod5=2

8a+5=5b+2=37

a=4,b=7

ans=37
@Logrhythm i think there would be more cases instead of 50...

49+48 , 49+47, 49+46, 49+45 and so on... will not be complemented.
similaryly, 48 + 47, 48+46 and so on....


@The_Loser said:
bhai kya kiya hai ye?
my mistake
a 7spaces b
due to a nd b=2
spaces 7 alphabets 26 due to repetition 26^7*2 ?
@The_Loser said:
in hw many ways alphabet of letter be arranged so that dre are 7 letters bw a & b.
26C7*2!*7!*18!
@The_Loser two cases

1. a _ _ _ _ _ _ _ b - 26^7
2. b _ _ _ _ _ _ _ a - 26^7 since each blank/alphabet can be filled with 26 letters..

Answer---> 26^7*2!
@sunnychopra89 said:
[(1!)^(1!) + (2!)^(2!) + (3!)^(3!) + ............ + (1000!)^(1000!)] / [2^3 X 5^1].Find the Remainder.
37 ?
from 5!^5! remainder will be 0
[2^3 X 5^1]=x
(1!)^(1!)/x=1
(2!)^(2!)/x=4
(3!)^(3!)/x=16
4!^4!/x=16

total 37/x=R=37






@
@bs0409 said:
Use CRT

Let Nr=X
then Xmod8=5

also, Xmod5=2

8a+5=5b+2=37

a=4,b=7

ans=37
Could u plz telme in brief what is CRT/Chineese Remainer Theorem.
@sunnychopra89 said:
@bs0409 Could u plz telme in brief what is CRT/Chineese Remainer Theorem.
Write Denominator as a*b where a and b are coprime to each other.
Find Nr mod a (=x say) and Nr mod b (=y say).

then solve am+x=bn+y for m and n in integers. the value will be the remainder....

examination
fr 1st 3 papers = max marks 50
4th exm - max marks 100
find no f ways one can score 60% ?

Which among 2^1/2, 3^1/3, 4^1/4, 6^1/6 and 12^1/12 is the largest?

3^1/3.

@The_Loser said:
examination fr 1st 3 papers = max marks 504th exm - max marks 100find no f ways one can score 60% ?
exactly 60% or more than 60%??
@bs0409 said:
Write Denominator as a*b where a and b are coprime to each other.
Find Nr mod a (=x say) and Nr mod b (=y say).

then solve am+x=bn+y for m and n in integers. the value will be the remainder....
How to calculate x and y....I'm a bit confused...:(
If you hav a subset of integers to chosen bet. 1 to 3000, such that no integers add up to multiple of nine, what can be the max number of elements in the subset?

1. 1668
2. 1332
3. 1333
4. 1334

@shattereddream said:
If you hav a subset of integers to chosen bet. 1 to 3000, such that no integers add up to multiple of nine, what can be the max number of elements in the subset?1. 16682. 13323. 13334. 1334
considering 1 and 3000 are not included
9k+1-333
9k+2-334
9k+3-333
9k+4-333
9k+5-333
9k+6-333
9k+7-333
9k+8-333
9k-333

we can have 9k+1,9k+2,9k+3,one among9k+4/9k+5 and one 9k no

334+333*3+1 =1334
@Subhashdec2 said:
considering 1 and 3000 are not included9k+1-3339k+2-3349k+3-3339k+4-3339k+5-3339k+6-3339k+7-3339k+8-3339k-333we can have 9k+1,9k+2,9k+3,one among9k+4/9k+5334+333*3 =1333
i was getting 1336 first
@shattereddream said:
If you hav a subset of integers to chosen bet. 1 to 3000, such that no integers add up to multiple of nine, what can be the max number of elements in the subset?1. 16682. 13323. 13334. 1334
9k+1 --> 333
9k+2 --> 334
9k+3 --> 333
9k+4 --> 333
one 9k no.
total --> 1334