fin3sse

MGMAT instructor that went to HBS said that a 4 is enough.

I think that the Manhattan Challenge Problem Archive is a little harder than the actual GMAT. What is great is that you get practice on a CAT-like environment so it helps. However, I recommend that you finish OG 11, then the OG Quantitative Workout before moving onto MGMAT. Hope this helps.

Very nice question. Thanks.

I got n=4. Here's my calculations: ---------------------------------------------------- From the first part of the problem: k = 5.1 x 10^n ---------------------------------------------------- k = 5.1 x 10^n k = 51 x 10^(n-1) k^2 = 51^2 x 10^(2*(n-2)) k^2 = 2601 x 10^(2n-2) -------------------------------------------------------- From the second part of the problem: k^2 = 2.601 x 10^9 -------------------------------------------------------- k^2 = 2.601 x 10^9 k^2 = 2601 x 10^6 -------------------------------------------------------- Setting first and second parts equal to each other -------------------------------------------------------- k^2 (from first part) = k^2 (from second part) 2601 x 10^(2n-2) = 2601 x 10^6 This implies that: 2n - 2 = 6 2n = 8 n = 4

For the third question, I got 1/24. There's only one combination that follows x^2-(by)^2, and that is when (x-y) is multiplied by (x+y). So the numerator is 1. The denominator can be found by taking the permutation of the four choices, which is 4*3*2*1 = 24. Therefore, my answer is 1/24.

For the second question, I got B. Here's my line of reasoning: ----------------------------------------- Statement 1: n is divisible by 3 ----------------------------------------- Pick a even multiple of 3 and an odd multiple of 3. If you pick 3 and 6 as values of n, you'll see that n is divisible by 3, and it can be odd or even. Therefore, statement 1 is insufficient. ----------------------------------------- Statement 2: 2n is divisible by twice as many positive integers as n ----------------------------------------- Statement 2 is basically saying that every factor of n is a factor of 2n. Therefore, the difference between 2n and n is just that one factor of 2. Taking this further, we can infer that if 2n is divisible by twice as many positive factors as n, then n must only have one factor (other than 1), which means that n is a prime number. Since n is a prime number, it must be odd. Statement 2 is sufficient. Thus, I vote for choice B.

Another way is to graph it.

For the first question, I got B. I got it from the following: ----------------------------- From Statement 1: |x-3|>=y ----------------------------- This is insufficient. The question stem states that y>=0, and since you know that all absolute values will result in a positive number, x can be any value. ----------------------------- From Statement 2: |x-3| ----------------------------- If you multiply by -1 to both sides of the equation and switch the signs, you would get y=0. Taking those two pieces of information together, you would get y=0. If y=0, you can substitute zero into statement 2, and solve for x. As a result, x must be 3. Therefore, the final answer is B.

I find that one of the best ways to demystify inequalities is to graph them. First, start by plotting out the equation: zt = -3. You can try out different numbers, or you can just remember that the graph, y=1/x, looks like a hyperbola in the first and third quadrants. Then the graph, y= - 1/x, would be a hyperbola in the second and fourth quadrants (since you are reflecting it over the y axis). Therefore, the graph zt=-3 is the same graph as z = 3* (-1/t), which is a hyperbola offset by some constant in the second and fourth quadrants. Once you have that graph, you will need to factor in the inequality part of the equation. To do this, you know that when z=0 and t=0, it does not satisfy the equation, zt Now let's look at the statements: ------------------------------------- Statement 1: z -------------------------------------- If you draw a line on the graph that represents z = 9 and look at everything under that line, that represents z This is insufficient. ------------------------------------- Statement 2: t -------------------------------------- If you draw a line on the graph that represents t = -4 and look at everything to the left of that line, that represents t ------------------------------------- Both Statements Taken Together -------------------------------------- Look at the area below the line z = 9 and to the left of t = -4, and you'll see that there are shaded areas both above the line z = 4 and below z = 4. This means that z can be either above or below 4. This is insufficient. Therefore, the answer is E. Hope this helps.

I heard that anything above a 4 is good for the top schools.

I think that doing OG 11 again helps. Look into MGMAT tests online too.

Manhatttan and OG Verbal Review

Good luck! Also keep a grid of the questions that you got wrong

I found that writing things down helps. Also, don't time yourself first. Read it slow and try to go for proper comprehension of the passage (rather than speed). Focus on accuracy, not speed. Speed will come automatically with practice.

Wow. That is impressive.