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@Krusto, you almost got it right: Equation 1 x/(x+y) = n x = nx+ny (n-1)x + ny = 0 y/x = (1-n)/n Equation 2 x/(x-y) = m x = mx - my (m-1)x - my = 0 y/x =(m-1)/m y/x+y/x = [(1-n)/n + (m-1)/m] = [(1-n)m + (m-1)n]/[nm] = (m-mn+mn-n)/mn= (m-n)/mn hence, (y/x)*2=(m-n)/mn; (y/x)=(m-n)/2mn; x/y=2mn/(m-n) w...

by beatthegmat.garry

Mon Mar 05, 2012 4:29 am
Forum: Problem Solving
Topic: Algebra
Replies: 10
Views: 1811

Hi Folks,

Are we talking about GMAT or any standardized test in general? Can GRE be used as a surrogate?

Thanks,
Garry


Why do you consider permutations here?

by beatthegmat.garry

Wed Sep 21, 2011 7:09 pm
Forum: Problem Solving
Topic: A jewelry store sells customized rings
Replies: 10
Views: 4637

Assuming angle x is angle(BCD)......
Since AD || BC, angle(BCD) and angle z are supplementary (they add upto 180 degrees).
So the question is reduced to finding what the value of angle z.

statement 1: no info about angle z

statement 2: z=40.

Hence B.

Thanks !

by beatthegmat.garry

Sun Aug 21, 2011 7:02 pm
Forum: Data Sufficiency
Topic: a data from gmat club
Replies: 2
Views: 894

Let n1, n2 and n3 be the 3 numbers: statement 1: Mean=3 and Median=3 therefore, (n1+n2+3)/3=3 .......n3=3. n1+n2=6. the possible combinations of n1 and n2 are (0,6)(1,5)(2,4)(3,3) Statement 2: Mode=3. Hence more than one number will be 3. Since n3 is assumed to be 3 we have either n1=n2=3. Hence C. ...

by beatthegmat.garry

Sun Aug 21, 2011 6:50 pm
Forum: Data Sufficiency
Topic: Mean and Mode
Replies: 5
Views: 1501

Thanks Frankenstein :)

by beatthegmat.garry

Mon Aug 15, 2011 10:10 pm
Forum: Data Sufficiency
Topic: Jars ratio
Replies: 6
Views: 1202

Let total number of possible ways of selecting any 2 marbles be 'S'. probability of selecting 2 red marbles=8C2/S=28/S. ......(i) probability of selecting 1 red and 1 white marble=8C1*YC1/S. ...... (ii) Now if Y>=4 then YC1=4C1=4 which will render (ii) greater than (i). Statement (1): Y<=8 . No suff...

by beatthegmat.garry

Mon Aug 15, 2011 9:54 pm
Forum: Data Sufficiency
Topic: Jars ratio
Replies: 6
Views: 1202

We know that sqrt(a)*sqrt(b)=sqrt(ab). sqrt(9+sqrt(80)) sqrt(9-sqrt(80)=sqrt(9+sqrt(80)*(9-sqrt(80)) =sqrt(9^2-sqrt(80^2)) .................(a+b)(a-b)=a^2-b^2 =sqrt(81-80) =sqrt(1) =1 Hope this help :)

by beatthegmat.garry

Sun Aug 07, 2011 5:58 pm
Forum: Problem Solving
Topic: sqrt(9+sqrt(80)) sqrt(9-sqrt(80))=
Replies: 3
Views: 2442

Lets assume n1 be the no. of 8m ribbons. Lets assume n2 be the no. of 13m ribbons. Since total length=100, we can write: 8*n1 +13*n2=100 .........(1) Lets guess values of n1 and n2 such that eqn.(1) will be satisfied You will only find just one combination which is n1=6, n2=4. So I believe there are...

by beatthegmat.garry

Wed Aug 03, 2011 7:51 am
Forum: Problem Solving
Topic: ribbons in bag
Replies: 4
Views: 1267

In all you have 12 different combinations of head/tale and the numbers on the dice. You will have 6 ways to get a Tale and any number(from 1 to 6) on the dice. You will have 2 ways to get number 3 on the dice and any side (head or tale) of the coin. Please note that among the 8(6+2) favourable ways ...

by beatthegmat.garry

Sat Jul 30, 2011 6:49 pm
Forum: Problem Solving
Topic: Probability Man Guide
Replies: 4
Views: 1936

The quotient is not clear. Please use paranthesis where ever necessary

I see two kinds: (a) 5*(N^3)/8 (b) 5*N^(3/8)

by beatthegmat.garry

Sat Jul 30, 2011 1:51 pm
Forum: Problem Solving
Topic: probability again
Replies: 15
Views: 2936

If a number is divisible by 3^16 then the number should be able a multiple of 3^16. 63^n can be written as = (9*7)^n=(3^2 * 7)^n if you have noticed above each power of 63 will contribute 2 powers of 3 (i.e. 3^2). And for 63^n to be a multiple of 3^16 it has to contribute in atleast 16 powers of 3 (...

by beatthegmat.garry

Thu Jul 28, 2011 7:44 pm
Forum: Data Sufficiency
Topic: value of n?value of n?
Replies: 12
Views: 2032

Among any 3 consecutive integers you will find either 2 numbers one of them a multiple of 2 and the other a multiple of 3 or one number which is multiple of 6. Hence when you multiple 3 consecutive numbers the product will be a multiple of 6. From the above list 116 is the only number which is not a...

by beatthegmat.garry

Wed Jul 27, 2011 6:57 am
Forum: Problem Solving
Topic: 3 consecutives
Replies: 5
Views: 1195

x+y=3(x-y) ....given

(x+y)^2=3(x^2-y^2) .....multiplyin both sides by (x+y)

x^2 + y^2 +2xy=3x^2-3y2;

2xy=2x^2-2y^2;
xy/x^2-y^2=1

3xy/2(x^2-y^2)=3/2

Hence answer is 3/2 which is number 4.

by beatthegmat.garry

Sun Jul 17, 2011 8:44 pm
Forum: Problem Solving
Topic: Solve..
Replies: 5
Views: 1235

IMO the answer is E. Given: Also CD=8; AB=18 Statment1: C is in between A and B and hence CA=CB=9. Since CD=8 hence D is also in between A and B but we have no information whether its between A and C or B and C. So BD may be 1 or 17. Statement2: Since we dont get any information about the placement ...

by beatthegmat.garry

Sun Jul 17, 2011 8:13 pm
Forum: Data Sufficiency
Topic: Number Line
Replies: 3
Views: 1206