n dollars

Expert replies

j_shreyans: Legendary Member; Posts: 510; Joined: Thu Aug 07, 2014 2:24 amFollowed by: 5 members; Thanked: 3 times

by j_shreyans » Wed Oct 29, 2014 9:08 am

A driver paid n dollars for auto insurance for the year 1997. This annual premium was raised by p percent for the year 1998; for each of the years 1999 and 2000, the premium was decreased by 1/6 from the previous year's figure. If the driver's insurance premium for the year 2000 was again n dollars, what is the value of p?

A)12
B)100/3
C)36
D)44
E)50

OAD

Like this post

Source: Beat The GMAT — Problem Solving | Wed Oct 29, 2014 9:08 am

GMATGuruNY: GMAT Instructor; Posts: 15539; Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members; Location: New York, NY; Thanked: 13060 times; GMAT Score:790

by GMATGuruNY » Wed Oct 29, 2014 9:25 am

j_shreyans wrote:A driver paid n dollars for auto insurance for the year 1997. This annual premium was raised by p percent for the year 1998; for each of the years 1999 and 2000, the premium was decreased by 1/6 from the previous year's figure. If the driver's insurance premium for the year 2000 was again n dollars, what is the value of p?

A)12
B)100/3
C)36
D)44
E)50

Let n = 100.
We can PLUG IN THE THE ANSWERS, which represent the value of p.
When the correct answer choice is plugged in, the premium in 2000 = n = 100.

Answer choice D: 44
Since the premium increases by p% in 1998, the premium in 1998 = 100 + 44% of 100 = 144.
Since the premium decreases by 1/6 in 1999, the premium in 1999 = 144 - (1/6)(144) = 144 - 24 = 120.
Since the premium deceases by another 1/6 in 2000, the premium in 2000 = 120 - (1/6)(120) = 120 - 20 = 100.
Success!

The correct answer is D.

Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

Like this post

GMAT/MBA Expert

Brent@GMATPrepNow: GMAT Instructor; Posts: 16207; Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members; Location: Vancouver, BC; Thanked: 5254 times; GMAT Score:770

by Brent@GMATPrepNow » Wed Oct 29, 2014 9:57 am

j_shreyans wrote:A driver paid n dollars for auto insurance for the year 1997. This annual premium was raised by p percent for the year 1998; for each of the years 1999 and 2000, the premium was decreased by 1/6 from the previous year's figure. If the driver's insurance premium for the year 2000 was again n dollars, what is the value of p?

A)12
B)100/3
C)36
D)44
E)50

Here's an algebraic solution.

First recognize that increasing a value by p percent is the same as multiplying by (100 + p)/100
For example, increasing a value by 7% is the same as multiplying by (100 + 7)/100 [i.e. 1.07]
Likewise, increasing a value by 25% is the same as multiplying by (100 + 25)/100 [i.e. 1.25]

Also, recognize that decreasing a value by 1/6 is the same as multiplying by 5/6

Okay, let's begin.

Premium for 1997: n
Premium for 1998: [(100 + p)/100]n
Premium for 1999: (5/6)[(100 + p)/100]n
Premium for 2000: (5/6)(5/6)[(100 + p)/100]n

We're told that the premium for 2000 is n.
So, we can write: (5/6)(5/6)[(100 + p)/100]n = n
Divide both sides by n to get: (5/6)(5/6)[(100 + p)/100] = 1
Simplify: (25/36)[(100 + p)/100] = 1
Simplify: (25)(100 + p)/(36)(100) = 1
Simplify: (100 + p)/(36)(4) = 1
So we know that 100 + p = (36)(4)
Simplify: 100 + p = 144
So, p = 44

Answer: D

Cheers,
Brent

Brent Hanneson - Creator of GMATPrepNow.com

Like this post

Johnniewales: Newbie | Next Rank: 10 Posts; Posts: 6; Joined: Wed Jul 15, 2015 5:39 am

by Johnniewales » Tue Dec 08, 2015 6:50 am

Please what determines when we plug in? In some cases, we plug in
And the equation becomes messy. Then sometimes we don't plug in
Then realized we should have. Please help

Like this post

GMAT/MBA Expert

[email protected]: Elite Legendary Member; Posts: 10392; Joined: Sun Jun 23, 2013 6:38 pmFollowed by: 511 members; Location: Palo Alto, CA; Thanked: 2867 times; GMAT Score:800

by [email protected] » Tue Dec 08, 2015 9:39 am

Hi Johnniewales,

You ask a good question - much of the information that you're seeking will come from experience/practice though. Many of the Quant questions that you'll face on Test Day can be solved by TESTing VALUES or TESTing THE ANSWERS, while others are essentially just 'math questions' that require a few calculations to get to the solution. The good news is that GMAT is a predictable, standardized Test, so once you learn to spot the patterns in the questions, then you'll be able to select the most efficient way to go about solving the question.

You should post any GMAT questions that you have in these Forums, so that you can see how Experts and other Users solve them.

1) How long have you been studying?
2) What resources have you been using?

GMAT assassins aren't born, they're made,
Rich

Contact Rich at [email protected]

Like this post

Johnniewales: Newbie | Next Rank: 10 Posts; Posts: 6; Joined: Wed Jul 15, 2015 5:39 am

by Johnniewales » Tue Dec 08, 2015 2:13 pm

Thanks Rich,

I have been studying since July but just started using MGMAT series text books and the 60day guide in November,
I will be taking the exams in January 2016

Regards

Johnniewales

Like this post

GMAT/MBA Expert

[email protected]: Elite Legendary Member; Posts: 10392; Joined: Sun Jun 23, 2013 6:38 pmFollowed by: 511 members; Location: Palo Alto, CA; Thanked: 2867 times; GMAT Score:800

by [email protected] » Tue Dec 08, 2015 10:38 pm

Hi Johnniewales,

Since you've been studying for some time, how have you been scoring on your practice CATs (including the Quant and Verbal Scaled Scores)? And what is your goal score?

GMAT assassins aren't born, they're made,
Rich

Contact Rich at [email protected]

Like this post

Johnniewales: Newbie | Next Rank: 10 Posts; Posts: 6; Joined: Wed Jul 15, 2015 5:39 am

by Johnniewales » Wed Dec 09, 2015 9:19 am

Hi Rich,

I haven't been doing well, my score has just been between 420-480
Break down

Quant- 27
Verbal -22

My target score is between 700-750

I really need to improve my scores

Thanks

Like this post

GMAT/MBA Expert

[email protected]: Elite Legendary Member; Posts: 10392; Joined: Sun Jun 23, 2013 6:38 pmFollowed by: 511 members; Location: Palo Alto, CA; Thanked: 2867 times; GMAT Score:800

by [email protected] » Wed Dec 09, 2015 10:10 am

Hi Johnniewales,

I've sent you a PM with some suggestions.

GMAT assassins aren't born, they're made,
Rich

Contact Rich at [email protected]

Like this post

prada: Senior | Next Rank: 100 Posts; Posts: 64; Joined: Wed Dec 08, 2010 10:55 pm; Thanked: 1 times

by prada » Tue Feb 02, 2016 5:49 pm

[email protected] wrote:Hi Johnniewales,

You ask a good question - much of the information that you're seeking will come from experience/practice though. Many of the Quant questions that you'll face on Test Day can be solved by TESTing VALUES or TESTing THE ANSWERS, while others are essentially just 'math questions' that require a few calculations to get to the solution. The good news is that GMAT is a predictable, standardized Test, so once you learn to spot the patterns in the questions, then you'll be able to select the most efficient way to go about solving the question.

You should post any GMAT questions that you have in these Forums, so that you can see how Experts and other Users solve them.

1) How long have you been studying?
2) What resources have you been using?

GMAT assassins aren't born, they're made,
Rich

Hey Rich, when you say
The good news is that GMAT is a predictable, standardized Test, so once you learn to spot the patterns in the questions, then you'll be able to select the most efficient way to go about solving the question.

Can you elaborate on this a little?

Like this post

GMAT/MBA Expert

[email protected]: Elite Legendary Member; Posts: 10392; Joined: Sun Jun 23, 2013 6:38 pmFollowed by: 511 members; Location: Palo Alto, CA; Thanked: 2867 times; GMAT Score:800

by [email protected] » Tue Feb 02, 2016 7:09 pm

Hi prada,

Every prompt that you will face on Test Day is carefully designed - the wording, the numbers, even the wrong answers - are all carefully chosen to make the question fair AND to (often) provide you with more than one approach to get to the correct answer. Since GMAT scores are valid for 5 years, and those scores are comparable over time, just about everything that you'll see when YOU take the GMAT has shown up (in some way, shape or form) on everyone else's GMATs too (the exception is IR, which replaced a second essay prompt back in 2012).

Thus, you really shouldn't think about GMAT questions as 'isolated' prompts - they're based on established rules and patterns. Most Test Takers only focus on the 'knowledge' aspect of their studies though and completely ignore Tactics and the deeper built-in patterns of the Exam. 'Clues' to help you answer the question are often found in the answer choices or in the specific words used in the prompt. For example, in this prompt, the answers are all numbers, written in ascending order. Maybe we can use them 'against' the prompt. Since they're relatively 'spread out', maybe we can use estimation (instead of doing lots of long, drawn out math). With the proper training, you'll learn to spot all of those clues and take advantage of them.

GMAT assassins aren't born, they're made,
Rich

Contact Rich at [email protected]

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

559 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review