Official Quant thread for CAT 2013

@rkshtsurana said:
@19rsb yup shre d approach
bhai mera toh LAMBA hai......(method)......
multiplication method....thodi fast calculation chahiye....2^29=(2^30)/2=(1024^3)/2
=536870912.........4is missing.........not recommended if fast multiplication tricks r not known...
bhai dont know any special tricky method for dis ques...... oder dan multiplication.....
@rkshtsurana said:
oh sry ..but ans is 4..
toh sahi toh hai ...check my post.
@19rsb said:
bhai mera toh LAMBA hai......(method)......multiplication method....thodi fast calculation chahiye....2^29=(2^30)/2=(1024^3)/2=536870912.........4is missing.........not recommended if fast multiplication tricks r not known...bhai dont know any special tricky method for dis ques...... oder dan multiplication.....
trick is simple divide it by 9..remainder is 5 ..so 4 is missing ..
@19rsb said:
Recently smoking at public places is declared as an offence. Delhi Police has started imposinga penalty against smoking in public and has eight raid teams in place. In a surprise check, theraid team caught 40 people smoking in the Connaught Place area of Delhi. The standarddeviation and sum of squares of the amount found in their pockets were Rs. 10 and Rs. 40000,respectively. If the total fine imposed on these offenders is equal to the total amount found intheir pockets and the fine imposed is uniform, what is the amount that each offender will haveto pay as fine?(1) Rs. 90(2) Rs. 60(3) Rs. 30(4) Rs. 15OA is rs30....share ur approach also.....plz......
Edit : Let the ampunts be a1, a2, a3...a40
Avg = A = (a1+a2+...+a40)/40
and a1^2 + a2^2 +...+a40^2 = 40000
Standard deviation=10= root((A-a1)^2 + (A-a2)^2 +...+(A-a40)^2)/40)
=> 40A^2 = 3600
=> A = 30
So each hhas to pay 30 Rs..
@19rsb said:
Recently smoking at public places is declared as an offence. Delhi Police has started imposinga penalty against smoking in public and has eight raid teams in place. In a surprise check, theraid team caught 40 people smoking in the Connaught Place area of Delhi. The standarddeviation and sum of squares of the amount found in their pockets were Rs. 10 and Rs. 40000,respectively. If the total fine imposed on these offenders is equal to the total amount found intheir pockets and the fine imposed is uniform, what is the amount that each offender will haveto pay as fine?(1) Rs. 90(2) Rs. 60(3) Rs. 30(4) Rs. 15OA is rs30....share ur approach also.....plz......
@rkshtsurana ,@sujamait .......bhaiyon help me out wid dis prblm......
@19rsb said:
@rkshtsurana ,@sujamait .......bhaiyon help me out wid dis prblm......
bhai upar solve ho gayi hai..bus sahi hai...

kuch aur Qs dalo bhai log..office mein hangover ho rha hai..
@ScareCrow28 said:
Let the ampunts be a1, a2, a3...a8Avg = A = (a1+a2+...+a8)/40Standard deviation=10= root((A-a1)^2 + (A-a2)^2 +...+(A-a8)^2)/40)=> 40A^2 = 3600=> A = 30So each hhas to pay 30 Rs..
bhai throw sum lyt on....40A^2=3600........
@19rsb said:
bhai throw sum lyt on....40A^2=3600........
10= root((A-a1)^2 + (A-a2)^2 +...+(A-a8)^2)/40)
4000 = 40A^2 - 2*A*(a1+a2+...+a40) + (a1^2+a2^2...+a40^2)
=> 4000 = 40A^2 - 2A(40A) + 40000
Baki to prabhu ki daya se hojaega 😛

One hundred identical coins each with prob P of showing up heads are tossed once. If 0


1) 1/21
2) 49/101
3) 50/101
4) 51/101

P.S @sujamait ..hope this helps
Which of the following is the lowest?
(1) 30^2 –12^2 – 3^2 (2) 35^2 –14^2 – 6^2
(3) 30^2 –10^2 - 5^3 (4) 33^2 –17^2 - 1^2
@rkshtsurana said:
2^29 is a 9 digit number containing all distinct digits. Which number is missing ?
I proceeded this way
9 distinct digits sum =45(1+2+..9)= multiple of 3
so if the missing number will be multiple 3 then whole number wil be divisible by 3
so 0,3,6,9 can't be missing
mod[2^29,10], mod[2^29,100] = 2,1
so 0,3,6,9,2,1 can't be missing

Now first digit will be 5

2^1 = 2
2^2 = 4
2^3 = 8
2^4 = 16
2^5 = 32
2^6 = 64
2^7 = 128
2^8 = 256
2^9 = 512
2^10 = 1024
========= first digit starts repeating so first digit of 2^29=5
2^11 = 2048
2^ 12 = 4096
2^ 13 = 8192

so 0,3,6,9,2,1,5 can't be missing

Now we left with 4,7,8. Hope Koi ek hi option mai ho 😛

@ScareCrow28 said:
Which of the following is the lowest?(1) 30^2 –12^2 – 3^2 (2) 35^2 –14^2 – 6^2(3) 30^2 –10^2 - 5^3 (4) 33^2 –17^2 - 1^2
Option c
@ScareCrow28 said:
10= root((A-a1)^2 + (A-a2)^2 +...+(A-a8)^2)/40)4000 = 40A^2 - 2*A*(a1+a2+...+a40) + (a1^2+a2^2...+a40^2)=> 4000 = 40A^2 - 2A(40A) + 40000Baki to prabhu ki daya se hojaega
kya baat hai.......behtareen.....

Thoda explanation possible in detail? nahi samja concept behind this..


@sujamait
@rkshtsurana said:
trick is simple divide it by 9..remainder is 5 ..so 4 is missing ..
@ScareCrow28 said:
Which of the following is the lowest?(1) 30^2 –12^2 – 3^2 (2) 35^2 –14^2 – 6^2(3) 30^2 –10^2 - 5^3 (4) 33^2 –17^2 - 1^2
ye to direct ho jayega

1)42*18-9
2)21*49-36
3)20*40-125
4)50*16-1

option 3

@ScareCrow28 said:
Which of the following is the lowest?(1) 30^2 –12^2 – 3^2 (2) 35^2 –14^2 – 6^2(3) 30^2 –10^2 - 5^3 (4) 33^2 –17^2 - 1^2
3 lag rha hai..



soumitrabengeri
aapke Q mein kuch typo hai ?
@sujamait said:
1 lag rha hai..soumitrabengeriaapke Q mein kuch typo hai ?
haan bhai..edit karke bhi nahi jaa raha..0 is less than P is less than 1
The total number of relations that can be defined from a Set A to set B is 4096. If m and n are the number of elements in set A and set B respectively, find the total number of values the ordered pair (m,n) can take?
4
3
6
8
9
@ScareCrow28 said:
Which of the following is the lowest?(1) 30^2 –12^2 – 3^2 (2) 35^2 –14^2 – 6^2(3) 30^2 –10^2 - 5^3 (4) 33^2 –17^2 - 1^2
(3)

minimize positive term
maximize negative term
33^3 - 17^2 - 1^2 = 1089 - 290 = 799
30^2 - 10^2 - 5^3 = 900 - 225 = 675
@rkshtsurana said:
2^29 is a 9 digit number containing all distinct digits. Which number is missing ?
Let "x" be missing... Sum of numbers will be... (45-x)
Remainder when 2^29 is divided by 9 is= 5
So.. (45-x) = 9k+5
from here x=4 suffices
Hence ans : 4