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Register now and save up to $200 Available with Beat the GMAT members only code • Free Practice Test & Review How would you score if you took the GMAT Available with Beat the GMAT members only code • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE Available with Beat the GMAT members only code • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • Free Trial & Practice Exam BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • 5 Day FREE Trial Study Smarter, Not Harder Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • 5-Day Free Trial 5-day free, full-access trial TTP Quant Available with Beat the GMAT members only code ## Difficult GMAT Math Problems This topic has 2 expert replies and 32 member replies Goto page ### GMAT/MBA Expert beatthegmat Site Admin Joined 13 Feb 2006 Posted: 6715 messages Followed by: 966 members Upvotes: 1249 #### Difficult GMAT Math Problems Sat Apr 15, 2006 2:34 pm Here's a document with over 100 really tough GMAT math problems. If you can get through these easily, you probably don't need to prep much more for the math section. Attachments This post contains an attachment. You must be logged in to download/view this file. Please login or register as a user. Last edited by beatthegmat on Wed Oct 03, 2007 8:06 pm; edited 1 time in total heathermilne Newbie | Next Rank: 10 Posts Joined 14 Sep 2008 Posted: 4 messages Upvotes: 1 Sat Sep 20, 2008 6:35 am Here's another version of the same problem set, this one with the answers hidden. Print it out, solve the problems, then select all the text (CTRL+A) and turn it back to black to reveal the answers. Attachments This post contains an attachment. You must be logged in to download/view this file. Please login or register as a user. wilderness Master | Next Rank: 500 Posts Joined 15 Mar 2008 Posted: 102 messages Upvotes: 4 Fri Jul 18, 2008 5:54 am Dear GMAT Gurus, I am taking an average of 5 minutes to solve these tough questions. I know the average time we have on GMAT is 2, but I dont expect to have many questions of this difficulty in the exam. While working with OG, my average time is less than 2 min. So the question is What have been your averge time when you do these questions and do you think average of 5 min per question is acceptable. isisalaska Community Manager Joined 10 Dec 2006 Posted: 363 messages Followed by: 2 members Upvotes: 7 Wed Dec 13, 2006 3:43 pm are these problems more diffcult than the ones we will find in the GMAT test? are these problems more in line iwth the Kaplan 800 book? Thanks! _________________ Isis Alaska ### GMAT/MBA Expert beatthegmat Site Admin Joined 13 Feb 2006 Posted: 6715 messages Followed by: 966 members Upvotes: 1249 Wed Dec 13, 2006 10:43 pm isisalaska wrote: are these problems more diffcult than the ones we will find in the GMAT test? are these problems more in line iwth the Kaplan 800 book? Thanks! These problems are overall more difficult than the ones you would encounter on the GMAT (in line with Kaplan 800). They aren't as well written as real GMAT questions, but still good practice. Kansonne Junior | Next Rank: 30 Posts Joined 24 Jan 2007 Posted: 21 messages Mon Feb 05, 2007 9:02 pm Hi, Can anyone explain the solution to the first problem in this "gmat MATH tough problems.doc" set? Here's the problem and solution again: 1. The sum of the even numbers between 1 and n is 79*80, where n is an odd number, then n=? Sol: First term a=2, common difference d=2 since even number therefore sum to first n numbers of Arithmetic progression would be n/2(2a+(n-1)d) = n/2(2*2+(n-1)*2)=n(n+1) and this is equal to 79*80 therefore n=79 which is odd... My questions are... I tried plugging and chugging different values of n into the equation above, for example, n = 3. The sum of even numbers between 1 and 3 is 2, but with the formula in the solution, I get 12. What am I doing wrong? Thanks! ### GMAT/MBA Expert beatthegmat Site Admin Joined 13 Feb 2006 Posted: 6715 messages Followed by: 966 members Upvotes: 1249 Mon Feb 05, 2007 9:07 pm For your reference, here's the discussion thread for this problem: http://www.beatthegmat.com/viewtopic.php?t=406 Best of luck! art Newbie | Next Rank: 10 Posts Joined 24 Oct 2007 Posted: 1 messages Wed Oct 24, 2007 11:21 am n is the number of terms in the A.P. For even numbers between 1 and 3 (which is 2), n is 1 and not 3 Plug this into the formula ginger Newbie | Next Rank: 10 Posts Joined 20 Feb 2008 Posted: 2 messages Target GMAT Score: 700 Wed Feb 20, 2008 1:56 pm Can someone please email me the file with the difficult questions? It is not opening at all and I cannot open or save it. Thanks alot! meermaidrose@yahoo.com workhard_1978 Newbie | Next Rank: 10 Posts Joined 27 Feb 2008 Posted: 9 messages Thu Feb 28, 2008 2:33 am Eric, Where have these questions come from ?Kaplan,Princeton, Manhattan or OG ? Pls let me know jbeurg Newbie | Next Rank: 10 Posts Joined 25 May 2008 Posted: 1 messages Upvotes: 1 Test Date: June 26 Target GMAT Score: 85 Mon May 26, 2008 4:22 am beatthegmat wrote: Here's a document with over 100 really tough GMAT math problems. If you can get through these easily, you probably don't need to prep much more for the math section. Hi. I think there is an error in your document gmat MATH tough problems.doc. in #1, n=159, not 79. That is, 159=2n+1 is odd, using your n=79. Jbeurg[/quote] agoyal2 Senior | Next Rank: 100 Posts Joined 29 Feb 2008 Posted: 59 messages Upvotes: 4 Sat May 16, 2009 7:11 pm I am looking for a solution to the below problem: The price of a bushel of corn is currently$3.20, and the price of a peck of wheat is $5.80. The price of corn is increasing at a constant rate of 5x cents per day while the price of wheat is decreasing at a constant rate of root(2)*x-x cents per day. What is the approximate price when a bushel of corn costs the same amount as a peck of wheat? Did not understand the solution presented in the document that well... abhinav85 Master | Next Rank: 500 Posts Joined 29 Dec 2008 Posted: 179 messages Upvotes: 2 Test Date: not decided Target GMAT Score: 700 Mon May 18, 2009 1:31 pm Can somebody help in downloading this file. Its says .doc but i am unable to open it after downloading it??? NikolayZ Master | Next Rank: 500 Posts Joined 18 Jun 2009 Posted: 124 messages Upvotes: 35 Fri Jun 19, 2009 1:07 am agoyal2 wrote: I am looking for a solution to the below problem: The price of a bushel of corn is currently$3.20, and the price of a peck of wheat is \$5.80. The price of corn is increasing at a constant rate of 5x cents per day while the price of wheat is decreasing at a constant rate of root(2)*x-x cents per day. What is the approximate price when a bushel of corn costs the same amount as a peck of wheat?

Did not understand the solution presented in the document that well...
Hey mate.

Since you know the rate of both corn and wheat, you can assume that they will be equal through M days. And the differences in prices will be (rate*Mdays)

320 + (5x*Mdays) = 580 - (.41x*Mdays), then we can combine X and days into one variable.
I suppose you got what comes next =)

tohellandback Legendary Member
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Sat Jun 20, 2009 10:12 pm
are you sure the answers are correct..I did the first problem and I think it is done wrong

1. The sum of the even numbers between 1 and n is 79*80, where n is an odd number, then n=?
Sol: First term a=2, common difference d=2 since even number

therefore sum to first n numbers of Arithmetic progression would be

n/2(2a+(n-1)d)

= n/2(2*2+(n-1)*2)=n(n+1) and this is equal to 79*80

therefore n=79 which is odd...
now the n here is the number of terms in the series 2,4,6..
the real n being asked in the question should be 79*2+1=159

_________________
The powers of two are bloody impolite!!

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