Search found 69 matches
Well, if at any point you were allowed to add the same step twice, you would finish the sequence to 2x. 2^8 + 2^7 + 2^6 + 2^5 + (let's stop here and finish it up) 2^5 would be x + x/2 + x/4 + x/8 + x/8. But this isn't really important. You can see that the sum is getting closer and closer to 2x, not...
- by Feep
Tue May 05, 2009 8:39 pm- Forum: Problem Solving
- Topic: GPREP 2+2+(2^2)+(2^3)+(2^4)+(2^5)+(2^6)+(2^7)+(2^8)
- Replies: 8
- Views: 10313
Anyone familiar with binary will have absolutely no problem here, but if you're not, think about this: Let's call 2^8 "x". Therefore, 2^7 = 0.5x, 2^6 = 0.25x, 2^5 = 0.125x, and so on, down the line. Adding these up, you get progressively closer to 2x, and then finally, the 2 + 2 seals it. ...
- by Feep
Tue May 05, 2009 4:38 pm- Forum: Problem Solving
- Topic: GPREP 2+2+(2^2)+(2^3)+(2^4)+(2^5)+(2^6)+(2^7)+(2^8)
- Replies: 8
- Views: 10313
The trick here is to break down 990 into its prime factorization, which is 2 * 3 * 3 * 5 * 11. We absolutely NEED an 11 somewhere in the product to achieve 990, and then we just need to make sure the other prime factors are satisfied in the numbers 1-10. 2? Check. 3? Check. 5? Check. We need one mor...
- by Feep
Mon May 04, 2009 2:45 am- Forum: Problem Solving
- Topic: The least possible value for n
- Replies: 1
- Views: 1218
To me, it's C Since x is a positive integer, it is either 1,2,3,4,5,6,7,8 or 9, the average between x and 10 is either 5,5; 6; 6,5; 7; 7,5; 8; 8,5; 9 or 9,5 (1) tells us that z is closer to 10 than to x. (2) tells us that z=5x Let's start with (2): this tells us that, since x is either one of the n...
- by Feep
Sun May 03, 2009 7:24 pm- Forum: Data Sufficiency
- Topic: GMATPrep number properties
- Replies: 16
- Views: 6462
Feep, What about if you consider 0 or negative as part of the set of the first integers? the constraint for being greater than 1 is only for a and n, not for any members of the first integers. is it? Thanks. I completely agree. The question is worded vaguely in that respect and probably would never...
- by Feep
Sat May 02, 2009 6:09 pm- Forum: Data Sufficiency
- Topic: GMAT Prep
- Replies: 5
- Views: 1474
I arrived at D. (1) gives the range of k between 6,000 and 500,000. We know that k must equal 5.1, 51, 510, 5100, 51000, 510000, 5100000, etc.; the only number in this set that falls in the given range is 51,000, n is 4. Sufficient. (2) gives an exact value of k, which therefore gives an exact value...
- by Feep
Fri May 01, 2009 4:31 pm- Forum: Data Sufficiency
- Topic: value of k
- Replies: 3
- Views: 1296
Hey Feep, Option 2 is insufficient too a. What if x is 6 and z is 7. Z is closer to 10. the average of 6 and 10 is 8. it means z is less then the average b. what if x is 7 and z is 9 average of 7 and 10 is 8.5 it means z is greater Insufficient. it should be E First of all, I assume you were talkin...
- by Feep
Thu Apr 30, 2009 11:41 pm- Forum: Data Sufficiency
- Topic: GMATPrep number properties
- Replies: 16
- Views: 6462
So, we know that the average is 7, which means that (2 + 3 + 8 + 11 + x + y) = 7, or 24 + x + y = 42, or that x + y = 18. We also know that x < y, so x may in fact only be x < 9. For the median, we need to look at possible ranges of x. If x > 3, then the ordered set becomes {2, 3, x, 8, 11, y} or {2...
- by Feep
Wed Apr 29, 2009 12:55 am- Forum: Problem Solving
- Topic: Mean & Median (Faster Way Needed)
- Replies: 3
- Views: 3841
Looks like A to me. (1) tells us that z is closer to 10 than to x. Since the average of x and 10 will be exactly at the midpoint of those two numbers, z will be to the right of the midpoint on the number line, and is therefore greater. Sufficient. (2) gives us z = 5x. If x = 1, z = 5, and is NOT gre...
- by Feep
Mon Apr 27, 2009 8:32 pm- Forum: Data Sufficiency
- Topic: GMATPrep number properties
- Replies: 16
- Views: 6462
(1) states that anywhere from 6 to 10 of the employees are women. Let's look at both extremes: if it is 6, the probability that both will be selected is (6/10) * (5/9) = 30/90 = 1/3, less than 1/2. If it is 10, the probability that both will be selected is 100%, of course. Since we can yield two dif...
- by Feep
Sun Apr 26, 2009 12:55 am- Forum: Data Sufficiency
- Topic: Probability
- Replies: 1
- Views: 1050
I arrived at B. Quick little tip: both statements together essentially ask the test-taker to solve a^6 = 64, which also completely ignores the information given in the question. This makes it highly unlikely that the answer is C. It's just too easy. Why would they even ask it? And, obviously, it's n...
- by Feep
Sat Apr 25, 2009 8:57 pm- Forum: Data Sufficiency
- Topic: GMAT Prep
- Replies: 5
- Views: 1474
I'm not doubting that this question has merit. I merely ask, for the sake of everyone on this forum, that you mention in your posts that it is a question of your own design. Your questions, whether intentional or not, do differ in protocol from standard GMAT questions, and I want students to underst...
- by Feep
Sat Apr 25, 2009 2:35 pm- Forum: Problem Solving
- Topic: Remainder
- Replies: 6
- Views: 1764
This is the second question I've seen from you that seems highly unlikely to be actually asked on a real GMAT exam. When a number is stated as "a", it is usually implied that the number is a constant value, and yet you imply that "a" is a changing value. Does "b" also c...
- by Feep
Fri Apr 24, 2009 6:53 pm- Forum: Problem Solving
- Topic: Remainder
- Replies: 6
- Views: 1764
I find it hard to believe this hasn't been answered before, but... We know that an isosceles right triangle is, by definition, a 45-45-90 right triangle. Therefore, the hypotenuse will be sqrt(2) times the length of either of the sides. If the length of a side is s, the perimeter is 2s + s*sqrt(2). ...
- by Feep
Wed Apr 22, 2009 11:11 pm- Forum: Problem Solving
- Topic: GMAT Prep Question - Hypotenuse of a right isosles triangle
- Replies: 3
- Views: 1410
No, the answer to the question as stated is A. The only way it could be D is if the question stated if AND ONLY IF the integer r is in K, then r+1 is in K.
Something is wrong with the question or answer as presented in this thread.
- by Feep
Tue Apr 21, 2009 11:59 pm- Forum: Data Sufficiency
- Topic: DS doubt
- Replies: 13
- Views: 2017