Official Quant thread for CAT 2013

@joyjitpal said:
Boxes numbered 1,2,3,4 and 5 are kept in a row and they which are to be filled with either a red or a blue ball, such that no two adjacent boxes can be filled with blue balls. Then, how many different arrangements are possible, given that all balls of a given colour are exactly identical in all respects?(a) 8 (b) 10 (c) 15 (d) 22
Possible ways =2^5=32

Unfavourable= 2 B together, 3 B together, 4 B TOGETHER
2 B together

BBR _ _
RBBR_
_RBBR
_ _ RBB
TOTAL=4+2+2+4=12; Subtract 1 for double counting of BBRBB
so total=11
3 B together
BBBR_
RBBBR
_RBBB
TOTAL 5
4 B TOGETHER=1

TOTAL UNFAVOURABLE=17
FAVOURABLE=32-17=15?
@soumitrabengeri said:
I think answer should be 22For 0 blue balls---> 1 waysFor 1 blue ball-->5 waysFor 2 blue balls--->15 ways (5 ways for one and 3 ways for the other)For 3 blue balls---> 1 wayFor 4--->not possible
@joyjitpal
Can you explain the bold part ? BBRRR has total arrangements = 10 ways ! ( 5!/3!2!)

So, if we don't want B in adjacent boxes => Total - (when 2 Bs are together) = 10 - (4!/3!) = 6 ?

Also, another way _B_B_ , a + b + c = 3 -> a + b' + c = 2 => 4C2 = 6 ways ?

How did you get 15 ? 😞

R B R B R
R R B R B
B R B R R
B R R B R
R B R R B
B R R R B

What else ? 😞 I guess, I didn't get the question.

PS: I guess, today is my NONE OF THESE options Day :banghead:
@joyjitpal said:
Boxes numbered 1,2,3,4 and 5 are kept in a row and they which are to be filled with either a red or a blue ball, such that no two adjacent boxes can be filled with blue balls. Then, how many different arrangements are possible, given that all balls of a given colour are exactly identical in all respects?(a) 8 (b) 10 (c) 15 (d) 22
R R R R R - 1
R R R R B - 5
R R R B B - 6
R R B B B - 1

13
@gautam22 said:
sir main jaise kar raha tha....... 3 log hain to unko 1540 dediye har kisi ko.....ab 1540 bacha to 1540 3 se divide nahi hota........to matlab remainder aata hai...par agar do ke case 2310 ho gaya par ye further 2 se divide ho jata hai to reminder zero aa gaya......isme kuch galat kar raha hoon kya sir????????
Yes, this method works too, but the simpler method is to look at the factors with even powers . As I said, if n divides 4620, n^2 should not divide 4620 -> n^2 should not be in the original list of factors of 4620

In this case, 1 and 2 are in the factors as well as their squares 1 and 4 are. This method is faster, but your method is fine too 😃
@YouMadFellow said:
@joyjitpal Can you explain the bold part ? BBRRR has total arrangements = 10 ways ! ( 5!/3!2!) So, if we don't want B in adjacent boxes => Total - (when 2 Bs are together) = 10 - (4!/3!) = 6 ?Also, another way _B_B_ , a + b + c = 3 -> a + b' + c = 2 => 4C2 = 6 ways ?How did you get 15 ? R B R B RR R B R BB R B R RB R R B RR B R R BB R R R BWhat else ? I guess, I didn't get the question.PS: I guess, today is my NONE OF THESE options Day
Sorry..apologies
I considered just the 1st case where the ball is in the 1st position and applied the rule to all the balls..guess from your explanation my answer too would be none of these
@joyjitpal said:
Boxes numbered 1,2,3,4 and 5 are kept in a row and they which are to be filled with either a red or a blue ball, such that no two adjacent boxes can be filled with blue balls. Then, how many different arrangements are possible, given that all balls of a given colour are exactly identical in all respects?(a) 8 (b) 10 (c) 15 (d) 22
_ = 1 way
_B_ = 5 ways
_B_B_ => a + b' + c = 2 => 4C2 = 6 ways
B_B_B = 1 way

Total = 13
@gautam22 said:
sir even kyun any even odd power will work if there is an odd power >1....for ex:- divide 27 for d same question....... not possible......3^3........if each gets 9 we can further divide it......in d last case had dere been a factor of d form n^2x+1.....den we wud hav considered it as well..........plz correct me if i m wrong
Yes, so taking your example i.e. 27

n = 3 is rejected right ? Why ? Because 3^2 is a factor of 27 too , that's why

In general 27/n is an integer = k , given in the question, but (k/n) should not be as per the requirement

=> 27/(n^2) is NOT an integer ..

I didn't say take the final power of the prime factors, I said, if there is a possibility that an even power of the factor (n) exists, then reject that n.
Three labelled boxes containing red and white cricket balls are all mislabelled. It is known that one of the boxes contains only white balls and one only red balls. The third contains a mixture of red and white balls. You are required to correctly label the boxes with the labels red, white and red and white by picking a sample of one ball from only one box. What is the label on the box you should sample?

(a) White
(b) Red
(c) Red and White
(d) Not possible to determine from a sample of one ball
@grkkrg said:
_ = 1 way_B_ = 5 ways_B_B_ => a + b' + c = 2 => 4C2 = 6 waysB_B_B = 1 wayTotal = 13
Yes, I got the same.

Wondering why the wrong solution is roaming everywhere around the internet :|, or may be we are terribly wrong 😐

@chillfactor Sir, Can you look into these two questions -> Quoted one, and the one where Red and Blue balls are arranged 😃
@gautam22 said:
same sir 13 aa rahai mera1,5,6,1 ye case ban rahe hain ....par 13 to option mein hi nahi hai
Whts the OA?
@joyjitpal said:
Boxes numbered 1,2,3,4 and 5 are kept in a row and they which are to be filled with either a red or a blue ball, such that no two adjacent boxes can be filled with blue balls. Then, how many different arrangements are possible, given that all balls of a given colour are exactly identical in all respects?(a) 8 (b) 10 (c) 15 (d) 22
OA?

@joyjitpal said:
Three labelled boxes containing red and white cricket balls are all mislabelled. It is known that one of the boxes contains only white balls and one only red balls. The third contains a mixture of red and white balls. You are required to correctly label the boxes with the labels red, white and red and white by picking a sample of one ball from only one box. What is the label on the box you should sample?(a) White (b) Red (c) Red and White (d) Not possible to determine from a sample of one ball
Select the box with the red and white written on it
Since the box is incorrectly labelled, we can choose one ball from it
If the ball is white then that box contains only white balls and if it is red then only red
From this we can also identify the other 2 boxes since they are also incorrectly labelled
@joyjitpal said:
Three labelled boxes containing red and white cricket balls are all mislabelled. It is known that one of the boxes contains only white balls and one only red balls. The third contains a mixture of red and white balls. You are required to correctly label the boxes with the labels red, white and red and white by picking a sample of one ball from only one box. What is the label on the box you should sample?(a) White (b) Red (c) Red and White (d) Not possible to determine from a sample of one ball
c) Red and White ?

If we get Red when we pick from it, => The box marked Red is White, and the other one is Mixed

If we get White, => The box marked White is Red, and the other is mixed.
@joyjitpal said:
Three labelled boxes containing red and white cricket balls are all mislabelled. It is known that one of the boxes contains only white balls and one only red balls. The third contains a mixture of red and white balls. You are required to correctly label the boxes with the labels red, white and red and white by picking a sample of one ball from only one box. What is the label on the box you should sample?(a) White (b) Red (c) Red and White (d) Not possible to determine from a sample of one ball
(c) Red and White
@YouMadFellow said:
c) Red and White ?If we get Red when we pick from it, => The box marked Red is White, and the other one is MixedIf we get White, => The box marked White is Red, and the other is mixed.
:banghead: :|
@paridhi11890 said:
No Spamming :nono: .. Only smileys not allowed !
@joyjitpal said:
Three labelled boxes containing red and white cricket balls are all mislabelled. It is known that one of the boxes contains only white balls and one only red balls. The third contains a mixture of red and white balls. You are required to correctly label the boxes with the labels red, white and red and white by picking a sample of one ball from only one box. What is the label on the box you should sample?(a) White (b) Red (c) Red and White (d) Not possible to determine from a sample of one ball
C?
@joyjitpal said:
Three labelled boxes containing red and white cricket balls are all mislabelled. It is known that one of the boxes contains only white balls and one only red balls. The third contains a mixture of red and white balls. You are required to correctly label the boxes with the labels red, white and red and white by picking a sample of one ball from only one box. What is the label on the box you should sample?(a) White (b) Red (c) Red and White (d) Not possible to determine from a sample of one ball
(c) Red and White
x^3+y^3 -xythe maximum possible sum of x+y is
1).8
2)1
3)1.33
4)1.5
5)2
@joyjitpal said:
Boxes numbered 1,2,3,4 and 5 are kept in a row and they which are to be filled with either a red or a blue ball, such that no two adjacent boxes can be filled with blue balls. Then, how many different arrangements are possible, given that all balls of a given colour are exactly identical in all respects?(a) 8 (b) 10 (c) 15 (d) 22
13 ways
No B---1 way
1 B-----5 ways
2 B-----6 ways
3 B-----1 way
Total=13 ways