###### CATOfficial Quant Thread for CAT 2011 [Part 7]
the number of triangles whose vertices are at the vertices of an octagon but none of the sides of such triangle are taken from the side of the octagon?

please provide step by step soln.
thanx

total no of triangles-(triangles with 1 side common +triangles with 2 sides common)
nw total triangles will be 8c3=56
ans. 56-(32+8 )=16
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###### CATOfficial Quant Thread for CAT 2011 [Part 7]
Originally Posted by jeet_mba View Post
some one cud plz explain the best and shortest possible method to solve the below two questions:

1)There are ceratin no of pages in a book.'A' tore a certain page out of the book and later found the average of remaining pages no as 46 10/13.What where the pages missing?

2)There are certain consecutive natural nos,written on black board.one of them is erased and avg of remaining nos is 32 7/24.Whay is the missing no?

my take is
1. sum 115 page nos are 57 n 58

2. 18
if am rite ill post d approach
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###### CATOfficial Quant Thread for CAT 2011 [Part 7]
ksagarwa Says
A triangle has its angles in a GP. One of its interior angle is 60. What will be the nature of the triangle.

equilateral???
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###### CATOfficial Quant Thread for CAT 2011 [Part 7]
How many subsets of {1,2,3,4,5,6,7} do not contain two consecutive integers?
A)21
B)34
C)55
D)None

my take is 34 ways

null set-1
1 element set- 7
2 element set-15
3 element set-10
4 element set-1

am i rite??
• 1 Like
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###### CATOfficial Quant Thread for CAT 2011 [Part 7]
Some amount out of 6000 was lent out @ 10% p.a and the rest @ 20 p.a and thus in 4 yrs the total interest collected was 3400. whats the amt lent out at 10% p.a?

2500/2800/3200/3500

my take 3500

wats d oa??
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###### CATOfficial Quant Thread for CAT 2011 [Part 7]
Last question before leaving office.

a,b,c are in GP : 1,2,4

so : ax^2+2bx+c=0
x^2 + 4x + 4 = 0 :: (x+2)^2 = 0
roots : -2,-2

Let one root of the next equation be -2 other take 1.

so we have x^2 + x - 2 = 0

d=1,e=1/2,f=-2.

Check the options:

a/b = 1/2

b/e = 4

c/f = -2

Ye to kuch bhi nahi nikal raha............ :(

I need to leave

aapka approach toh sahi lag raha...answer kyun nahi nikla???
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###### CATOfficial Quant Thread for CAT 2011 [Part 7]
Q. If a 100 m wire is made available to fence 3 sides of a rectangular field, with the fourth side as a wall, what can be the maximum area of the field?

1. 2500
2. 2000
3. 1250
4 None of these.

my take is 1250! is it rite???
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###### CATOfficial Quant Thread for CAT 2011 [Part 7]
What is the number of distinct terms in the expansion of (a +b + c)^20?

(1) 231
(2) 253
(3) 242
(4) 210
(5) 228

is it 231???
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###### CATOfficial Quant Thread for CAT 2011 [Part 6]
1x120
2x60
3x40
4x30
5x24
6x20
8x15
10x12

reds won't be possible ..

so 4

achha lagta hai kabhi kabhi when you say "book galt hai ."

after finding d factors watever u did cud u pls xplain...im unable 2 understand
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###### CATOfficial Quant Thread for CAT 2011 [Part 6]
i have a slight problem in this one -

in a polygon the internal angles have a measure of 270 or 90 only. there 18 angles of the measure 270, find the number of angle with ameasur of 90.