Official Quant thread for CAT 2013

ravi.theja · January 11, 2013, 4:57am

@cadmium said:
Greatest number which can divide 1354,1866 and 2762 leaving the same remainder 10 in each case, is: A.64B.124C.156D.260After taking differences , what we'll have to do?Logical approach please.

the question can be considerd as find GCD of 1354-10 , 1866-10, 2762-10

==> GCD ( 1344, 1856,2752) = GCD ( 1856-1344 , 2752-1856 ) = GCD ( 512,896 ) = GCD is 128 :)

hw cum 64??

insane.vodka · January 11, 2013, 4:58am

@x2maverickc yea but still I was able to minimize the check to 11 to number...sometimes old ways takes 1min more...but chances of making error is 5%

insane.vodka · January 11, 2013, 4:59am

@ravi.theja said:
the question can be considerd as find GCD of 1354-10 , 1866-10, 2762-10==> GCD ( 1344, 1856,2752) = GCD ( 1856-1344 , 2752-1856 ) = GCD ( 512,896 ) = GCD is 128 hw cum 64??

1354 is not divisible by 128

x2maverickc · January 11, 2013, 5:00am

@ravi.theja

1344=2^6 * 21, 1852=2^6 * 29, 2752=2^6 * 43
how on earth GCD can't be 64 😛

ravi.theja · January 11, 2013, 5:01am

@insane.vodka said:
1354 is not divisible by 128

Reason for CAT '13

insane.vodka · January 11, 2013, 5:02am

@cadmium said:
Have you learned-by-heart all the 2^n powers ? Or did you implement some other logic which I am unable to figure it out?How come you concluded that 1344=2^6 * 21?

@cadmium I know 2^n till n = 10 ---> 1024

ravi.theja · January 11, 2013, 5:03am

@x2maverickc Error :P

insane.vodka · January 11, 2013, 5:04am

@ravi.theja said:
Reason for CAT '13

Mera signature dekh...wohi hoga jo mazuer-e-khuda hoga

cadmium · January 11, 2013, 5:09am

@insane.vodka said:
1354 is not divisible by 128

But 1344 is.

Also, it is mentioned in the question that remainder must be 10.

So, when 1354 is divided by 128 then remainder will be 10.

I don't understand where @ravi.theja has gone wrong.

Please correct me.

ravi.theja · January 11, 2013, 5:11am

@cadmium said:
But 1344 is.Also, it is mentioned in the question that remainder must be 10.So, when 1354 is divided by 128 then remainder will be 10.I don't understand where @ravi.theja has gone wrong. Please correct me.

1344 is NOT divisible by 128..!!check karo bhai

x2maverickc · January 11, 2013, 5:12am

@cadmium

check what you are saying. 1354 leaves a remainder of 64 when divided by 128. PM me if you are getting confused here.

Let's have some more questions.

insane.vodka · January 11, 2013, 5:15am

@cadmium Bhai kya kar rahe ho????

1344 = 2^6 * 29 hein na.... kabse bol rha huin

cadmium · January 11, 2013, 5:15am

@x2et02

@ravi.theja

Ya.

Thanks for rectifying. :-)

Got it now.

cadmium · January 11, 2013, 5:16am

@@ns123

Thanks. I was confused. Got it now.

cadmium · January 11, 2013, 5:18am

@insane.vodka said:
@cadmium Bhai kya kar rahe ho???? 1344 = 2^6 * 29 hein na.... kabse bol rha huin

Thanks. Got it now.

amrofa · January 11, 2013, 5:18am

The probability of a number n showing in a throw of dice marked 1 to 6 is
proportional to n.then the probability of the number 3 showing in throw is:
1. 1/2
2. 1/6
3. 1/7
4. 1/21

krum · January 11, 2013, 5:21am

@Amrofa said:
The probability of a number n showing in a throw of dice marked 1 to 6 isproportional to n.then the probability of the number 3 showing in throw is:1. 1/22. 1/63. 1/74. 1/21

1/7

Sum of all the factors of 18000 divisible by 8 but not by 25.

amrofa · January 11, 2013, 5:27am

@krum said:
1/7Sum of all the factors of 18000 divisible by 8 but not by 25.

(2^3 +2^4) (3^0 +3^1 +3^2) (5^0 + 5^1)
24*13*6=1872

amrofa · January 11, 2013, 5:29am

How many five-digit numbers can be formed such that it has following
properties :
I) It has at least one zero and at most 3 zeroes.
II) The non-zero digits are non-repeating.

9962 17378 12570 14398 15408

vbhvgupta · January 11, 2013, 5:49am

how many A.Ps are possible such that first term is 1235 and the last term is 3535 and there are atleast...
1. 3 terms
2. 4 terms
3. 5 terms
4. 6 terms

Can someone explain me the concept behind it????