Official Quant thread for CAT 2013

I am a posting a question highly irrelevant to the place where it is being posted

I have usually seen that IITians steal the show among the CAT 100 percentilers, SO i want to know whats in them which is not in non-IITian engineer and can that be developed. Please answer my question without being sarcastic or critical about me.I really want to know it.

I posted it here for 2 reasons :
1. I could not find a thread where this can be posted
2. I thought this is the place where I can recieve the max replies, off course many of you would post to criticize me or get sarcastic for the thread on which I am posting, But I still i believe that some of you will really want me to help

Please post the link to the thread where this question will be more germane
@iampg said:
Among 4 people A,B,C and D, A takes thrice as much as B to complete a piece of work. B takes thrice as much time as C and C takes thrice as much time as D to complete the same work. One group of three of the 4 men can complete the work in 13 days while another group of three can do so in 31 days. Which is the group that takes 13 days?a) A,B,D b)B,C,D c)A,C,D d)A,B,C
BCD??

A takes 9x days,
B 3x days, C takes x days, D takes x/3 days

the ratio.. A:B:C:D :: 27:9:3:1
so BCD takes 13 days and ACD takes 31 days.

@StructuredKevin said:
I am a posting a question highly irrelevant to the placewhere it is being postedI have usually seen that IITians steal the show among the CAT 100 percentilers, SO i want to know whats in them which is not in non-IITian engineer and can that be developed. Please answer my question without being sarcastic or critical about me.I really want to know it.I posted it here for 2 reasons :1. I could not find a thread where this can be posted2. I thought this is the place where I can recieve the max replies, off course many of you would post to criticize me or get sarcastic for the thread on which I am posting, But I still i believe that some of you will really want me to helpPlease post the link to the thread where this question will be more germane
here is your link or you can go to shout box...you'll get hell lot of replies there :
http://www.pagalguy.com/discussions/official-cat-2013-aspirants-25088203/3610422

Please dont spam again...lets keep this thread as clean as possible....


@x2maverickc said:
abc=177/3; where a,b,c are real and positive. What is the minimum value of (a+b+c)*(ab+bc+ca)?1. 1772. 354/33. 3544. 531
531??

(a+b+c) >= 3(abc)^1/3
ab+bc+ca >= 3(ab*bc*ca)^1/3
so minimum value of (a+b+c)*(ab+bc+ca) = 9*(abc)
= 531..

Q3

@vbhvgupta said:
A is twice as efficient as B and together they do the same work in as much time as C and D. If C and D can complete the work in 20 and 30 days respectively working alone, thn in how many days A can complete the work individually?
18 days...

1/a + 1/2a = 1/20 +1/30
a=18 days

@vbhvgupta said:
Q3


3: 1??

@saurav205 said:
3: 1??
explain?
@vbhvgupta said:
Q3
W/A-W/B=W/2n
W/A+W/B=W/n
W/A=3W/4n
A=4n/3

W/B=W/4n
B=4n

efficiency is work done per hour
3W/4n : W/4n
3:1
@vbhvgupta said:
explain?
1/a - 1/b = (1/a + 1/b)*1/2

putting the given condition in form of an equation

putting the given condition if the form of an equation :

1/a - 1/b = 1/2*(1/a +1/b)

at the request of @DeAdLy :


A positive integer is written on each faces of a cube. At each corner (vertex) of the cube, the product of the numbers on the faces that meet at the corner is written. The sum of the numbers written at all the corners is 2431. Find the sum of the numbers written on all the faces of the cube?

OA by midnight
courtesy Test Funda
sorry if this question has already been posted by someone else...

Q4

A and B together can do a piece of work in 80 days. B and C can do it in 120 days. All the three started their work together on the first day, but A bunked on every odd numbered day and C bunked on every even numbered day. How long did the work last?
(A)88 days
(B)90 days
(C)96 days
(D)98 days
ďťż
Simhapuri Express departs from Hyderabad at 3 am on Friday for Chennai. Charminar Express left Hyderabad at 4 am on the same day for Chennai. Charminar Express overtakes Simhapuri exactly at a distance of 200 km from Hyderabad at 8 am on Friday. After reaching Chennai, Charminar Express halts there for 1 hour and returned to Hyderabad. At a distance, which is 100 km from Chennai, it meets the Simhapuri Express, which is still on the way to Chennai. Assume, in return journey also, the average speed is the same and there is no stop in between Hyderabad and Chennai.
At what time did Charminar reach Hyderabad?
(A) 9 am on Saturday
(B) 8 am on Sunday
(C) 8 pm on Sunday
(D) 9 am on Sunday
A train after travelling 30 km from the starting point A develops a snag and therefore reaches the terminal B late by 15 minutes. Had it developed the snag 12 km ahead, it would have arrived 6 minutes sooner. Find the distance between the two stations A and B.
(A) 56 km
(B) 60 km
(C) 64 km
(D) 80 km
(E) 100 km
A transportation company specializes in hauling goods between Lucknow and Varanasi. Travelling time between the two cities is 9 hours. The trucks leave daily at 6 AM and continue to do so until 9 PM in each direction. Once the trucks reach the other city, the drivers rest there for 15 hours and then they come back. All the trucks have the same speed, follow the same path and do not stop in between.What is the maximum number of trucks, a driver will meet on the way and at what time will that driver leave?
15, at 12 PM
17, at 1 PM
17, at 2 PM
16, at 3 PM

Kindly provide solution for above questions

@vbhvgupta said:
Q4
12 days?

4/x(x + 7) = 3/(x + 7)(x - 10)
x = 20,-14(neglecting)

x + 10 = 30 men
30 *d = 18*20
d = 12 days

Q 5