Official Quant thread for CAT 2013

@jain4444 2.4?
@jain4444 said:
aur sir jii hum apse sikhte aa rahe hai Sohan and Rohan cut a regular hexagon and regular octagon out of circular papers of radius 20 each.find difference between perimeters of hexagon and octagon1.62.422.6
2.4??not sure
@jain4444 said:
aur sir jii hum apse sikhte aa rahe hai Sohan and Rohan cut a regular hexagon and regular octagon out of circular papers of radius 20 each.find difference between perimeters of hexagon and octagon1.62.422.6
2.4
@jain4444 said:
aur sir jii hum apse sikhte aa rahe hai Sohan and Rohan cut a regular hexagon and regular octagon out of circular papers of radius 20 each.find difference between perimeters of hexagon and octagon1.62.422.6
2.4

1. Given a set A={1,2,3,4,5} B= {a,b,c} f:A->B
Find the :

a. Total Number of functions
b. Number of Surjective functions
c. Number of into functions
d. Number of bijective functions
e. Number of injective functions

Any idea about this ??

@deedeedudu said:
2.4
appraoch diyo
@pankaj1988 said:
2.4
@Brooklyn said:
appraoch diyo
Petya's mother sends him to the market with a red and a green bag to buy 10 carrots and 6 radishes.On his way home, Petya distributes the vegetables into 2 bags in such a way that no bag is empty. In how many ways can he do this?
@grkkrg said:
Petya's mother sends him to the market with a red and green bag to buy 10 carrots and 6 radishes.On the way home, Petya distributes the vegetables into 2 bags in such a way that no bag is empty .In how ways can he can do this?
30 ??
@grkkrg said:
Petya's mother sends him to the market with a red and a green bag to buy 10 carrots and 6 radishes.On his way home, Petya distributes the vegetables into 2 bags in such a way that no bag is empty. In how many ways can he do this?
64 ?
@Brooklyn said:
Bhai I have used cosine rule
For Hexagon :
cos (360/6) = (20^2+20^2-m^2)/(2*20*20)
m=20=>perimeter=20*6=120
For octagon:
cos (360/8)=(20^2+20^2-n^2)/(2*20*20)
n=sqrt(234.3)=>perimeter=8*sqrt(234.3)=8*15.3=122.4
(sqrt(234) is approx 15.3)
Difference in perimeter=122.4-120=2.4

@grkkrg said:
Petya's mother sends him to the market with a red and a green bag to buy 10 carrots and 6 radishes.On his way home, Petya distributes the vegetables into 2 bags in such a way that no bag is empty. In how many ways can he do this?
a+b=10
=>11c1=11

0,6
1,5
2,4
3,3
4,2
5,1
6,0

so 11*7=77

77-2=75
@krum said:
a+b=10=>11c1=110,61,52,43,34,25,16,0so 11*7=7777-2=75
no bag empty !!
@Brooklyn said:
no bag empty !!
-2 is taking care of that
@rubikmath said:
64 ?
@krum said:
a+b=10=>11c1=110,61,52,43,34,25,16,0so 11*7=7777-2=75
@krum said:
-2 is taking care of that
didnt get u
@rubikmath said:
64 ?
approach
@Brooklyn said:
didnt get u
distribute 10 carrots in 2 bags => (10 + 2 - 1)C(2 -1) = 11
distribute 6 radishes in 2 bags => (6 + 2 - 1)C(2 - 1) = 7

total = 11 * 7 = 77
But the red bag is empty in one case and the green bag in another.

So 77 - 2 = 75
@Brooklyn said:
didnt get u
first distribute 10 carrots , so 11 ways, including 0,10 and 10,0

now for each 11 case, there are 7 ways of distributing radishes , so total = 11*7=77

but these includes 2 cases which are not valid

that is when red bag had 0,10 and 0,6 and same for green bag, so 77-2=75
@jain4444 said:
aur sir jii hum apse sikhte aa rahe hai Sohan and Rohan cut a regular hexagon and regular octagon out of circular papers of radius 20 each.find difference between perimeters of hexagon and octagon1.62.422.6
cos 60=(2r^2-x^2)/(2r^2)
=>x=r

cos 45=(2r^2-y^2)/(2r^2)
=>y=r*_/(2-_/2)=
0.7653*r

8*0.7653*20 - 6*20
=122.448 - 120
=2.448

2.4