Search found 143 matches
Can someone tell me a quick way to decode a problem like this? If you start to solve each number in the sequence manually, you can see that it's alternating from positive to negative. But, how do you arrive at an approximate sum quickly? "For every integer k from 1 to 10, inclusive, the kth te...
- by krusta80
Mon Mar 05, 2012 3:25 pm- Forum: Problem Solving
- Topic: For every integer k from 1 to 10...
- Replies: 15
- Views: 8926
#61 in the official guide - data sufficiency "At a certain picnic, each of the guests were served either a single scoop or a double scoop of ice cream. How many of the guests were served a double scoop of ice cream?" (1) At the picnic, 60 percent of the guests were served a double scoop o...
- by krusta80
Mon Mar 05, 2012 1:55 pm- Forum: Problem Solving
- Topic: Is it the wording?
- Replies: 5
- Views: 1177
ok, clear now x-intercept=t+4/m not x=t+4/m thanks Mike and this is really strange equation here as krusta allows substitution of t=x only for x-intercept. I would say this is very special case valid for x-intercept only, correct me if i'm wrong. My mistake was not being more careful differentiatin...
- by krusta80
Mon Mar 05, 2012 1:05 pm- Forum: Data Sufficiency
- Topic: X intercept
- Replies: 12
- Views: 1397
Number 84 in official guide problem solving. Obviously they don't expect anyone to plug in here and do the math, it would take forever. What's the esoterica I'm supposed to know? "A dealer originally bought 100 identical batteries at a total cost of q dollars. If each battery was sold at 50 pe...
- by krusta80
Mon Mar 05, 2012 10:22 am- Forum: Problem Solving
- Topic: What am I supposed to be seeing?
- Replies: 4
- Views: 1048
yes exactly, not confusion- minor issue to which I referred initially x= -b/m =! t+ 4/m because you obtained x=-b/m when y=0 and could obtain x=t+4/m when y=-4. Do you see this? Ah, I finally found your mistake...hopefully we can put this to rest now: You said that I obtained x = t + 4/m, but I did...
- by krusta80
Mon Mar 05, 2012 9:04 am- Forum: Data Sufficiency
- Topic: X intercept
- Replies: 12
- Views: 1397
WOW! With real MATLAB graphic! Thanks so much!!!! Question 2 2x - 3y < x^2 Part (1) 2x - 3y = -2 Since x^2 can never be less than 0, we know that the main inequality will always hold true. SUFFICIENT Part (2) x > 2 and y > 0 The y > 0 tells us that we will always be subtracting from the 2x, which w...
- by krusta80
Mon Mar 05, 2012 7:16 am- Forum: Data Sufficiency
- Topic: GMATPrep DS Obstacles
- Replies: 12
- Views: 1685
Oh yeah...C is better because it avoids the passive case. Sorry to confuse!winniethepooh wrote:Any answers, experts?
- by krusta80
Mon Mar 05, 2012 7:14 am- Forum: Sentence Correction
- Topic: Is 'when' justified?
- Replies: 5
- Views: 1614
you are equating one point in space (x-y) to another point in space (x-y). Nobody says you cannot keep the same line equation with slope for the different coordinates. But to equate two coordinates as one is not allowed. Care to reconsider? Perhaps the source of confusion is the following line from...
- by krusta80
Mon Mar 05, 2012 7:09 am- Forum: Data Sufficiency
- Topic: X intercept
- Replies: 12
- Views: 1397
@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) ...
- by krusta80
Mon Mar 05, 2012 4:33 am- Forum: Problem Solving
- Topic: Algebra
- Replies: 10
- Views: 1823
Two sets of 4 consecutive positive integers have exactly one integer in common. The sum of the integers in the set with greater numbers is how much greater than the sum of the integers in the other set? A. 4 B. 7 C. 8 D. 12 E. 15 The only way that the overlap can be exactly one is if the last integ...
- by krusta80
Mon Mar 05, 2012 4:28 am- Forum: Problem Solving
- Topic: Two sets of 4
- Replies: 2
- Views: 6844
hi krusta , i spotted some minor issues in your solution and decided to feedback. Please follow my analysis carefully before standing with your approach affirmed :) The bold green part , here you set y=0 and find x-intercept - agree y=mx+b and y=0 <> 0=mx+b, x=-b/m The bold blue part , here you sup...
- by krusta80
Mon Mar 05, 2012 4:17 am- Forum: Data Sufficiency
- Topic: X intercept
- Replies: 12
- Views: 1397
Equation 1 x/(x+y) = n x = nx+ny (n-1)x + ny = 0 x/y = n/(1-n) Equation 2 x/(x-y) = m x = mx - my (m-1)x - my = 0 x/y = m/(m-1) x/y = (x/y + x/y)/2 = [n/(1-n) + m/(m-1)]/2 = [(m-1)n + (1-n)m]/[(1-n)*(m-1)] = (m-n)/[(1-n)*(m-1)] From here, I am unable to get it to convert to choice D. Maybe some slee...
- by krusta80
Sun Mar 04, 2012 11:57 pm- Forum: Problem Solving
- Topic: Algebra
- Replies: 10
- Views: 1823
lol.. prob try the other way arnd.. If |x|<>|y|, xy<>0, x/(x+y) = n, and x/(x-y) = m, then x/y= ? a) 3mn/2 b) 3m/(2n) c) n(m+2)/2 d) 2mn/(m-n) e) (n^2 - m^2)/(nm) This one is probably best solved using substitution. Let's try x = 2 and y = 3... n = 2/5 m = -2 x/y = 2/3 a) 3mn/2 = -6/5 NOPE b) 3m/(2...
- by krusta80
Sun Mar 04, 2012 9:00 pm- Forum: Problem Solving
- Topic: Algebra
- Replies: 10
- Views: 1823
Can you please clarify these parts? Is it x^2*y or x^(2y)?gopinathhyd wrote:Is X<Y
1. X^2Y = 8
2. Y^2X = 8
- by krusta80
Sun Mar 04, 2012 8:56 pm- Forum: Data Sufficiency
- Topic: Exponents and equations
- Replies: 5
- Views: 1021
If |x|<>|y|, xy<>0, x/(x+y) = n, and x/(x-y) = m, then x/y= ? a) 3mn/2 b) 3m/(2n) c) n(m+2)/2 d) 2mn/(m-n) e) (n^2 - m^2)/(nm) This one is probably best solved using substitution. Let's try x = 2 and y = 3... n = 2/5 m = -2 x/y = 2/3 a) 3mn/2 = -6/5 NOPE b) 3m/(2n) = -15/2 NOPE c) n(m+2)/2 = 0 NOPE...
- by krusta80
Sun Mar 04, 2012 8:20 pm- Forum: Problem Solving
- Topic: Algebra
- Replies: 10
- Views: 1823