CAT 2008: QQAD Practice Test Discussions

[PaglaMota]

Originally Posted by coolbryan_love

Can u explain how u got these values...m sure u din went for hit n trial..it ll be too time consumin....

hehe not that much pagal....see the imp. thing is a^2 - b =1.

then only +/- sqrt (b) will get cancelled....

so the first set 2,3 3,8......b = perfect squares -1 and a = root of that perfect square .....9 values as b cant be 0.

similarly other set, b= perfect squares and a = sqrt of b +1

so 10 values b =1,4,....100

total 19....

[PaglaMota]

Q 13....

area AOB : area DOC = 9:4

We can assume assume AB = 3x DC = 2x
height of the trapezium = 10/x (from area of 2 triangles)

area of trapezium = 0.5*(AB + DC)*10/x = 0.5*5x*10/x = 25....

option (d) is fine....but why asking minimum area when the area is constant?

[PaglaMota]

Q 12....

case1: coloring all with diff colors : 5*4*3*2 = 120
case2: any one of opposite blocks (n-s or e-w) same color and others diff. color = 5*4*3*2 = 120 (last 2 for n-s + e-w)
case3: opp. blocks same color on both n-s and e-w = 5*4 = 20

total 260 option (a)

[milindagrawal]

Guys.... as far as I know, discussions pertaining to questions are not allowed before the Official keys are posted.
So kindly wait till each one posts his/her answers.
Discussions can start after 1 tomorrow when the official keys are out.

[vaibhav2cool]

Originally Posted by PaglaMota

hehe not that much pagal....see the imp. thing is a^2 - b =1.

then only +/- sqrt (b) will get cancelled....

so the first set 2,3 3,8......b = perfect squares -1 and a = root of that perfect square .....9 values as b cant be 0.

similarly other set, b= perfect squares and a = sqrt of b +1

so 10 values b =1,4,....100

total 19....

for the second case b should be a perfect square and should be 1 greater than square root of a
so no pair exists..
hence answer is 9

[dewan_iitr]

My take in 50 mins -

2 - b
4 - c
6 - a
7 - d
9 - d
10 - e
11 - c
12 - a
13 - d
15 - c
19 - a
22 - b
23 - c

13 attempts

---------------
solved these after 50 mins -
3 -b
16 - e
17 - d
18 - e


--------

@Aarav - Sir I am facing this problem of less attempts. Though accuracy is good most of the times. In mocks as well i am stuck with 1 or 2 quests for abt 5-8 mins.
Even in this test I wasted 7-8 mins in 3rd quest which was damm simple. I was able to do that after exam in a zippy...
Comments??

[dewan_iitr]

My fav. quest. from test - ques. 13

sol.
let area of other 2 traingles be x and y
AOD - x
COB -y

now 4/y = x/9 [Good concept... can be used in many problems]
xy=36

x+y min = 12 when x=y
so min area for quad is 25

[kk_sonam]

my attempt

1. a
2. b
3. b
5. d
6. a
7. d
8. b
10. d
11. c
15. c
16. e
17. d
18. e
22. b


thank you for the test sir

[prakharc]

In 50 mins

1 b
2 b
3 b
4 c
5 c
6
7 d
8
9 d
10 c
11 c
12 a
13 e
14 c
15 c
16 e
17 d
18
19 a
20 b
21
22 b
23 e
24
25 e

Attempted 19....though not sure of my accuracy....

[ayan gupto]

Thanxx a lot Aarav for the test (some real sitters this time!!!!)

My Attempts :

1-b
2-b
3-b
5-e
7-c
8-c
9-d
10-b
12-a
14-b
15-c
16-e
17-d
22-b
23-e
24-a


Total 16 attempts in 50 mins.

Eagerly waiting for the results.