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A child selected a three-digit number, XYZ, where X, Y and Z denote the digits of the number and X + Y + Z= 10. If no two of the three digits were equal, what was the three-digit number? (1) X < Y < Z (2) The three-digit number selected was even. (1) x< y< z can be 1 +2+7, 2+3+5 different sets of t...

by kstv

Sat Jun 12, 2010 9:15 am
Forum: Data Sufficiency
Topic: Three digit number
Replies: 9
Views: 4504

TTr²/24² = (22/7) * 10*10/24*24
22/7 is very close to 21/7 = slightly more then 3
so 10*10/8*24
again 24*8 is very close to 25*8
or slightly less than 200
the approximation made in the numerator 22/7 will balance out
the approximation in the denominator
left with 10*10/200 = 1/2

by kstv

Sat Jun 12, 2010 8:22 am
Forum: Problem Solving
Topic: A circular mat with diameter 20 inches is placed on a square
Replies: 5
Views: 6239

Centre is O (-2,-3) . Pt A (-2,1) is inside the circle. Dist OA is 4 - y coordianates ( -3 to 1) x coordiantes are same. The radius is > 4
Pt B (4,-3) so OB is 6 ( -2 to 4) , here y coordinate is - 3.
The radius is < 6.
The radius is an integer.
Left with no options other than B.

by kstv

Sat Jun 12, 2010 12:24 am
Forum: Problem Solving
Topic: Circles
Replies: 2
Views: 958

1 to 35 has 18 odd 1 - 3 - 5 -..... 33- 35 No one can get 35 or 33 marbles, cos there will not be enough left for choosing the other 4. If one gets 31 marble the rest four get 1 each. So there are 16 odd numbers to choose. My guess is 15 C 4 cos if you choose the 4 odd numbers the fifth one has to b...

by kstv

Fri Jun 11, 2010 12:48 am
Forum: Problem Solving
Topic: Permutation combination sum
Replies: 6
Views: 4915

If x = 100a
then y = 25a ( y 1/2 of 1/2 of x or 1/4 of x)
25a % of x i.e (25a/100) * 100a = 100

25a² = 100

a = + - 2

since x is + so IMO C

by kstv

Wed Jun 09, 2010 11:51 pm
Forum: Problem Solving
Topic: Percentage Conundrum
Replies: 8
Views: 4252

If xy=-6, what is the value of xy(x+y)? (1) x-y=-5 (2) xy^2=18 from (2) xy² = 18 , but xy = -6 so y = 18/-6 = -3 so x = 2 but (1) x-y = -5 but if x = 2 & y = -3 , x-y = +5 not -5 though the answer is still B. cos x-y = + or - y , when substituted in xy = -6 will result in a quadratic eq. like y²+...

by kstv

Wed Jun 09, 2010 11:33 pm
Forum: Data Sufficiency
Topic: If xy=-6, what is the value of xy(x+y)?
Replies: 7
Views: 5217

x²+y²<=100 all points within the the circle with radius 10 and origin (0,0) is the region Q 1) a+b = 14 the point (8,6) - 64+36 or (6,8) - 36+64are on the circle. (7,7) - 49+49 < 100 is inside the circle, but (9,5)- 81 + 25 > 100 is outside Q. 2) a > b Not sufficient. Combining (1) & (2) & assumin...

by kstv

Wed Jun 09, 2010 7:36 am
Forum: Data Sufficiency
Topic: Manhattan Challenge Problem
Replies: 2
Views: 1013

Of 60 animals, 2/3 are either pigs or cows = 40 1) Twice as many cows as pigs, but 40 is not perfectly divisible by 3 so it can be 26 cows and 14 pigs , but 26 is not twice of 14 rather it must be 27 cows and 13 pigs . Suff. 2) More than 12 pigs , so less than 28 cows. Insuff. Together also Insuffic...

by kstv

Sat Jun 05, 2010 7:31 pm
Forum: Data Sufficiency
Topic: Of the 60.....
Replies: 5
Views: 1413

If n is an integer and x^n - x^-n = 0, what is the value of x ? (1) x is an integer. (2) n ≠ 0 x^n - 1/x^n = 0 ((x^n)² -1 /x^n = 0 so the numerator is = 0 (x^n)² - 1 = 0 (x^n+1)(x^n-1) = 0 x^n = 1 , & if n≠ 0 then x = 1. x^n = -1 & if n ≠ 0 then x is -ve and n is a odd no. (2) is not suffice...

by kstv

Thu Jun 03, 2010 1:40 am
Forum: Data Sufficiency
Topic: Help! Ron!?!
Replies: 8
Views: 1451

14 have > = 4 yrs experience
so 16 have < 4 yrs experience
3 of them have no degree
so 13 of them have degree and < 4 yrs exp.
Total no of degree holders = 18
5 = 18-13 have degree and > 4yrs exp.

by kstv

Wed Jun 02, 2010 3:47 am
Forum: Problem Solving
Topic: og 12 problem of degree
Replies: 3
Views: 1125

pradeepkaushal9518 wrote:what is the unit digit of (13)^4(17)^2(29)^3?

A.9
B.7
C.5
D.3
E.1

plz give the best way to find out the unit digit
just consider the unit digits
(3^4) *(7^2) *(9^3)
Even while calculating 3^4 , notice that the unit digit is 3*3 = 9*3 = ..7*3=..1
7^2 = 49
29^3 = 9*9 = 81*9=..9
now 1*9*9 = ...1

by kstv

Wed Jun 02, 2010 3:26 am
Forum: Problem Solving
Topic: OG 12 unit problem
Replies: 3
Views: 1417

Is the range of a combined set (S,T) bigger than the sum of ranges of sets S and T ? 1. The largest element of T is bigger than the largest element of S. 2. The smallest element of T is bigger than the largest element of S. The range of the combined set of (S,T) will be less than the sum sets S and ...

by kstv

Wed Jun 02, 2010 12:34 am
Forum: Data Sufficiency
Topic: range
Replies: 5
Views: 1450

The other forums have OA as E. This is a tough one for me partly cos of the wording. Too much of perfect tense in the options. Newborh Kangaroos use developed forelimbs to climb to their mother's pouch. Marsupial lions had developed forelimbs. Conclusion is that they needed to climb to their mothers...

by kstv

Wed Jun 02, 2010 12:14 am
Forum: Critical Reasoning
Topic: marsupial lions
Replies: 11
Views: 3669

sohaib_iba wrote:In an election where there are only 2 candidates one who gets 43% of the votes is rejected by a majority of 420 votes. The total number of votes polled is

A) 1290
B) 1300
C) 1710
D) 3000
loser gets 43% Winner gets 57% Diff = 14%
14% of votes = 420
100% of votes = (420/14)*100

IMO D

by kstv

Tue Jun 01, 2010 10:58 pm
Forum: Problem Solving
Topic: Need helpp
Replies: 3
Views: 1146

I do agree that there is emphasis on genetic makeup more than on environmental factors. Both in C and D it is clear that if you plant tomatoes you get the a yield of tomotoes . Should one rule out C cos nowhere in the paragraph is it mentioned that the environmental factors can have a detrimental ef...

by kstv

Tue Jun 01, 2010 3:03 am
Forum: Critical Reasoning
Topic: Kaplan CR Verbal workbook
Replies: 6
Views: 1413