Events & Promotions
|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Jun 0308:30 AM PDT
-09:30 AM PDT
In Episode 7 of our GMAT Ninja CR series, we are rounding up the oddballs, the misfits, and the format-benders: EXCEPT, Fill-In-The-Blanks, and other unusual Critical Reasoning question types. When you see a question that ends with a literal blank line
May 2910:00 AM IST
-11:00 PM IST
Start your journey with a fully customized action plan and work with a dedicated mentor to achieve a 735+ score.- Jun 04
08:30 AM PDT
-09:30 AM PDT
For most test takers, Data Insights is the most challenging section on the GMAT, with test takers scoring several points lower on average on DI than on Quant or Verbal and completing the section with less time to spare. - Jun 10
06:00 AM PDT
-06:15 PM PDT
Register for the GMAT Club Virtual MBA Spotlight Fair – the world’s premier event for serious MBA candidates. This is your chance to hear directly from Admissions Directors at nearly every Top 30 MBA program..
Lnstnbass4
Joined: 17 Dec 2016
Last visit: 10 Apr 2019
Posts: 9
Own Kudos:
Given Kudos: 53
Location: United States (VA)
Schools: Kelley '21
GMAT 1: 450 Q21 V24
GPA: 3.81
14 Apr 2018, 07:17
Kudos
Bookmarks
Hello
I am having difficulty with how to simplify addition and subtraction under a square root. Below is the problem and how it is stated in the Foundations of Math Manhattan Prep book. I also attached a copy of me trying to work out the problem. (AJ-WORK1 AND AJ-WORK2) The other attachment is the solution info that the book provides which isn't that clear to me. If someone can explain what I am doing wrong or how to look at this problem in a different way as well as some other examples perhaps ; that would be really great.
QUESTION #56 from Chapter 3 in FOM
Simplify the following root:Express expressions as integers
√(36^2 +15^2)
Thanks in advance
Felling super frustrated-AJ
I am having difficulty with how to simplify addition and subtraction under a square root. Below is the problem and how it is stated in the Foundations of Math Manhattan Prep book. I also attached a copy of me trying to work out the problem. (AJ-WORK1 AND AJ-WORK2) The other attachment is the solution info that the book provides which isn't that clear to me. If someone can explain what I am doing wrong or how to look at this problem in a different way as well as some other examples perhaps ; that would be really great.
QUESTION #56 from Chapter 3 in FOM
Simplify the following root:Express expressions as integers
√(36^2 +15^2)
Thanks in advance
Felling super frustrated-AJ
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
Attachments
AJ-EXPLANTION-56.pdf [73.07 KiB]
Downloaded 62 times
AJ-WORK2.pdf [118.87 KiB]
Downloaded 57 times
AJ-WORK1.pdf [112.3 KiB]
Downloaded 58 times
15 Apr 2018, 09:53
Kudos
Bookmarks
Hi Lnstnbass4,
I guess you made a mistake when you taking \(3^2\) out.
\(\sqrt{36^2+15^2}\)=\(\sqrt{(2^2*3^2)^2+(3*5)^2}\)=\(\sqrt{2^4*3^4+3^2*5^2}\)=\(\sqrt{3^2(2^4*3^2+5^2)}\)=\(\sqrt{3^2(16*9+25)}\)=\(\sqrt{3^2(144+25)}\)=\(\sqrt{3^2*169}\)=\(\sqrt{3^2*13^2}\)=3*13=39
Hope this helps!
I guess you made a mistake when you taking \(3^2\) out.
\(\sqrt{36^2+15^2}\)=\(\sqrt{(2^2*3^2)^2+(3*5)^2}\)=\(\sqrt{2^4*3^4+3^2*5^2}\)=\(\sqrt{3^2(2^4*3^2+5^2)}\)=\(\sqrt{3^2(16*9+25)}\)=\(\sqrt{3^2(144+25)}\)=\(\sqrt{3^2*169}\)=\(\sqrt{3^2*13^2}\)=3*13=39
Hope this helps!
20 Apr 2018, 13:40
Kudos
Bookmarks
Lnstnbass4
There's a quick way to solve this problem. (That's true on a lot of GMAT problems where the numbers seem too big to work with. They know you don't have a calculator, and they aren't really interested in testing your arithmetic skills beyond the basics, so if it looks like you might have to do a ton of arithmetic to solve a problem, there's probably another way to do it.)
Here's the right thought process for this problem.
1. There isn't really a math rule for adding together exponents, like 36^2 + 15^2.
2. However, there are two situations where you might see something like this on the test.
3. One is where you have two exponents with the same base added together, like 84^2 + 84^3. When you see this, factor out a common term. For instance, 84^2 + 84^3 = 84^2(1 + 84).
4. Another is where you're using the Pythagorean Theorem on a right triangle. That's a^2 + b^2 = c^2, or √(a^2 + b^2) = c.
5. Does this problem look like one of those two situations? It doesn't look like the first one, but it could look like the second one. Are 15 and 36 two sides of a right triangle?
6. A ratio of 15 to 36 is the same as a ratio of 15/3 to 36/3, or 5 to 12. There's a special right triangle that has sides with a ratio of 5 to 12! It's a (5,12,13) triangle.
7. Therefore, (5*3)^2 + (12*3)^2 = (13*3)^2.
8. Rephrasing that: sqrt(15^2 + 36^2) = sqrt(39^2) = 39.
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
