Official Quant thread for CAT 2013

@ScareCrow28 said:
We have k identical mugs. In an n-storey building, we have to determine the highest floor from which, when a mug is dropped, it still does not break. The experiment we are allowed to do is to drop a mug from a floor of our choice. How many experiments are necessary to solve the problem in any case, for sure? P.S. I just know the answer..so i won't give any options
for larger values of 'k', expression will be a bit complicated

for k = 2, minimum no of experiments will be 'a', where a is the smallest integer such that
a(a + 1)/2 ≥ n

for k = 3, minimum no of experiments will be 'a', where a is the smallest integer such that
summation a = 1 to a {a(a + 1)/2} ≥ n
=> a(a + 1)(a + 2)/6 ≥ n

In general for k = r, minimum no of experiments will be 'a', where a is the smallest integer such that
(summation a) from a = 1 to a {(r - 1) times} ≥ n

OR, for k = r, it will be a, where
C{(a + r - 1), r} ≥ n
@ananthchief said:
In a locality, the most read newspapers are " Hindu" , "TOI" and "IE" . 60% of the residents read at most one of these newspapers. 30% of the residents read exactly two of these newspapers. The number of residents who read all these papers is 5/6th of those who read none of the papers. 10% read "Hindu" and "TOI" but not "IE" . 40% read Hindu or "TOI" but not "IE" . 44% of residents read "Hindu".. 12% read only "TOI" and "IE". 2400 residents read only "Hindu" and "IE"Q) How many residents read TOIa) 2800 b)4200 c)3500 d) 4900Q) How many residents don't read any of the 3 newspapersa) 2400 b)3600 c) 3000 d) 4800Please provide answers with detailed solutions
1b and 2b?

H = a
HT = b
T = c
TI = d
I = e
IH = f
THI = g
none = h

Given :
h + a + c + e = 60%______________(1)
b + d + f = 30%_________(2)
g = 5h/6 or h = 6g/5
b = 10%
a +b + c = 40%____________(3)
a + b + f + g = 44%___________(4)
d = 12%
f = 2400

from (2), f = 8%
from (3), a + c = 30% or c = 30% - a
from (4), a + g = 26% or g = 26% - a
from (1), 6/5 (26% - a) + a + 30% - a + e = 60%
156% - 6a + 5e = 150%
e = 6/5*(a -1)

a + b + c + d + e + f + g + h = 100%
a + 10 + 30 - a + 12 + 6/5*(a-1) + 8 + 11/5*(26 - a) = 100
6a - 6 + 286 - 11a = 200
a = 16%
c = 14%
e = 18%
g = 10%
h = 12%
------------------------------------------------
Q1 answer:
c = 14% = 14 * 2400/8 = 4200

Q2 answer:
h = 12% = 12 * 2400/8 = 3600
Q) Determine the remainder when the number 1+22+33+4444+...+(sss...s times) written in base s+1, is divided by s-1.

Don't know the answer. Will the answer vary from base to base?

guys i have found in this thread the use of fermat theorem and eular theorem for finding out remainder of complex number. guys please explain both the theorem in detail, so that application used by u guys can be understood easily.

@ananthchief said:
In a locality, the most read newspapers are " Hindu" , "TOI" and "IE" . 60% of the residents read at most one of these newspapers. 30% of the residents read exactly two of these newspapers. The number of residents who read all these papers is 5/6th of those who read none of the papers. 10% read "Hindu" and "TOI" but not "IE" . 40% read Hindu or "TOI" but not "IE" . 44% of residents read "Hindu".. 12% read only "TOI" and "IE". 2400 residents read only "Hindu" and "IE"Q) How many residents read TOIa) 2800 b)4200 c)3500 d) 4900Q) How many residents don't read any of the 3 newspapersa) 2400 b)3600 c) 3000 d) 4800Please provide answers with detailed solutions
2nd ka 3600 aaya hai..1st ka option not matchin!
@Torque024 said:
Q) Determine the remainder when the number 1+22+333+4444+...+(sss...s times) written in base s+1, is divided by s-1.Don't know the answer. Will the answer vary from base to base?
@Torque024 said:Q) Determine the remainder when the number 1+22+33+4444+...+(sss...s times) written in base s+1, is divided by s-1.Don't know the answer. Will the answer vary from base to base?
for binary
1
for base 3
(1+22)base 3 = 1+ 8=9/2 = 1
for base 4
1+22+333 base 4,
1+10+3+12+48 = 64/3 =1
one in all cases.


@gautam22 said:
sir jab atmost 1 vala 60 hai 2 vala 30 hai to 3 vala 10 apne aap hi hogaya..
arre haan sahi kaha sirji
@eni said:
guys i have found in this thread the use of fermat theorem and eular theorem for finding out remainder of complex number. guys please explain both the theorem in detail, so that application used by u guys can be understood easily.
http://www.pagalguy.com/news/remainders-reloaded-euler-fermat-wilsons-theorems-cat-2011-a-19067
@Torque024 said:
Q) Determine the remainder when the number 1+22+33+4444+...+(sss...s times) written in base s+1, is divided by s-1.Don't know the answer. Will the answer vary from base to base?
0 lag rha ahi..
@sauravd2001
@sauravd2001 said:
are i did it diferently
for aod we have base as 8 ....draw perpendicular bisector weh ave perpendicular as 3
for foe we have base as 2 and then drawing perpendicular bisector we have perpendicular as .75
then =(.5*.75*2)/.5*8*3=1:16
yaar suarav , can you explain with diagram?
@milestogo3 said:
@Torque024 said:Q) Determine the remainder when the number 1+22+33+4444+...+(sss...s times) written in base s+1, is divided by s-1.Don't know the answer. Will the answer vary from base to base? for binary1for base 3(1+22)base 3 = 1+ 8=9/2 = 1for base 41+22+333 base 4,1+10+3+12+48 = 64/3 =1one in all cases.
Let s=9
1+22+333+4444+...+99999999=1097393685 in base 10
divide by s-1=8
mod[685]=5
Where am I wrong?
@ananthchief said:
In a locality, the most read newspapers are " Hindu" , "TOI" and "IE" . 60% of the residents read at most one of these newspapers. 30% of the residents read exactly two of these newspapers. The number of residents who read all these papers is 5/6th of those who read none of the papers. 10% read "Hindu" and "TOI" but not "IE" . 40% read Hindu or "TOI" but not "IE" . 44% of residents read "Hindu".. 12% read only "TOI" and "IE". 2400 residents read only "Hindu" and "IE"Q) How many residents read TOIa) 2800 b)4200 c)3500 d) 4900Q) How many residents don't read any of the 3 newspapersa) 2400 b)3600 c) 3000 d) 4800Please provide answers with detailed solutions
only H = 12
only TOI = 28
only IE = 8
H + TOI = 10
IE + TOI = 12
H + IE = 8
all three = 10
none = 12

@s @sujamait confirm karna bhai
A cube of side 'a' is converted into a sphere by adding clay on all the faces of the cube. The minimum volume of clay required is ?
We are given 1997 distinct positive integers, any 10 of which have the same least common multiple. Find the maximum possible number of pairwise coprime numbers among them.
@grkkrg Thanks for the detailed reply :)
@jain4444 that's right 😃 thanks for the reply
@ScareCrow28 said:
A cube of side €˜a €™ is converted into a sphere by adding clay on all the faces of the cube. The minimum volume of clay required is ?
radius of sphere=_/3a/2

clay required=volume of sphere - volume of cube

(_/3pi/2 -1)*a^3
@ScareCrow28 said:
A cube of side €˜a €™ is converted into a sphere by adding clay on all the faces of the cube. The minimum volume of clay required is ?
a^3 * (pi * sqrt(3)/2 - 1) ?

diameter of sphere = diagonal of the cube
2r = a sqrt(3)
volume of clay required = 4/3 pi r^3 - a^3
= a^3 * (pi * sqrt(3)/2 - 1)
@ScareCrow28 said:
A cube of side €˜a €™ is converted into a sphere by adding clay on all the faces of the cube. The minimum volume of clay required is ?
4/3*pi*(root3/2*a)^3-a^3
=>4/3*pi*3root3/8*a^3-a^3
=>a^3(root3/2*pi-1)
@eni said:
guys i have found in this thread the use of fermat theorem and eular theorem for finding out remainder of complex number. guys please explain both the theorem in detail, so that application used by u guys can be understood easily.
http://www.pagalguy.com/news/remainders-reloaded-euler-fermat-wilsons-theorems-cat-2011-a-19067

shoot any doubts if u have