Tom, who has 50 math questions, will get 5 points

Expert replies

Previous Topic Next Topic

VJesus12: Legendary Member; Posts: 2276; Joined: Sat Oct 14, 2017 6:10 amFollowed by: 3 members

by VJesus12 » Thu Jun 28, 2018 5:09 am

Timer

00:00

Answers

Stats

Difficulty—

Tom, who has 50 math questions, will get 5 points per question if he chooses a correct answer. If he chooses a wrong answer to a question or skips one, he will lose 2 points per question. Then, which of the following can be the score if he solves all the 50 questions?

A. 192
B. 193
C. 194
D. 195
E. 196

The OA is the option C.

I had no clue, how to solve this question without knowing the number of questions he attempted correct/wrong.

Please help.

Like this post

Source: Beat The GMAT — Problem Solving | Thu Jun 28, 2018 5:09 am

regor60: Master | Next Rank: 500 Posts; Posts: 416; Joined: Thu Oct 15, 2009 11:52 am; Thanked: 27 times

by regor60 » Thu Jun 28, 2018 7:11 am

VJesus12 wrote:Tom, who has 50 math questions, will get 5 points per question if he chooses a correct answer. If he chooses a wrong answer to a question or skips one, he will lose 2 points per question. Then, which of the following can be the score if he solves all the 50 questions?

A. 192
B. 193
C. 194
D. 195
E. 196

The OA is the option C.

I had no clue, how to solve this question without knowing the number of questions he attempted correct/wrong.

Please help.

One way to do this is to use some algebra:

Let C equal the number of questions answered correctly. Since there are 50 questions in total, that means 50-C are the number answered incorrectly.

The total score then would give 5 points credit for each correct answer, or 5xC, and subtract 2 points for each question answered incorrectly, or 2x(50-C)

So the total score is represented by 5C - 2(50-C), which can be reduced to 7C - 100.

Then test each of the possible total scores given as potential answers, for example:

7C - 100 = 194 therefore 7C=294.

And determine whether the result can be divided by 7 resulting in an integer.

Like this post

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

Tom's test

by GMATGuruNY » Thu Jun 28, 2018 8:25 am

VJesus12 wrote:Tom, who has 50 math questions, will get 5 points per question if he chooses a correct answer. If he chooses a wrong answer to a question or skips one, he will lose 2 points per question. Then, which of the following can be the score if he solves all the 50 questions?

A. 192
B. 193
C. 194
D. 195
E. 196

Since each question is worth 5 points, a perfect score on the 50-question test = 50*5 = 250.
For every question missed, Tom will forgo the 5 points attributed to the question and will lose another 2 points for missing the question, for a net loss of 7 points per missed question.
Thus, Tom's score = 250 - 7a, where a is the number of missed questions.
The expression in blue must be equal to one of the five answer choices.
If a=8, then Tom's score = 250 - (7*8) = 194.

The correct answer is C.

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

Jeff@TargetTestPrep: GMAT Instructor; Posts: 1462; Joined: Thu Apr 09, 2015 9:34 amFollowed by: 22 members; Location: New York, NY; Thanked: 39 times

by Jeff@TargetTestPrep » Mon Jul 30, 2018 10:29 am

VJesus12 wrote:Tom, who has 50 math questions, will get 5 points per question if he chooses a correct answer. If he chooses a wrong answer to a question or skips one, he will lose 2 points per question. Then, which of the following can be the score if he solves all the 50 questions?

A. 192
B. 193
C. 194
D. 195
E. 196

Let r = the number of questions he answered correctly and let w = the number of questions he answered incorrectly. So we have r + w = 50. We are asked to determine which value in the given choices can be 5r - 2w.

Notice that w = 50 - r, so 5r - 2w = 5r - 2(50 - r) = 5r - 100 + 2r = 7r - 100. If r = 42, we have 7(42) - 100 = 194. So 194 can be his score.

Answer: C

Jeffrey Miller
Head of GMAT Instruction
[email protected]

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

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] » Sun Aug 05, 2018 6:32 pm

Hi VJesus12,

We're told that Tom, who has 50 math questions, will get 5 points per question if he chooses a correct answer and he will lose 2 points if he chooses a wrong answer to a question or skips one. We're asked which of the following COULD be the score if he solves all 50 questions.

In certain Quant questions, if you don't immediately see a simple algebraic solution, then it sometimes helps to 'brute force' a bit of the math until you see a pattern emerge. Given the 'scoring rules' that this question lays out, here are some possible score outcomes for Tom:

Answers ALL 50 correct = (50)(5) = 250 points
Answers 49 correct, 1 wrong = (49)(5) - 2(1) = 243
Answers 48 correct, 2 wrong = (48)(5) - 2(2) = 236
Answers 47 correct, 3 wrong = (47)(5) - 2(3) = 229
Etc.

Notice how with every additional wrong (or skipped) question, Tom's score drops 7 points. THAT pattern will get you to the correct answer (you can just continue 'subtracting 7' until you find the match). That would lead to possible scores of 222, 215, 208, 201 and 194.

Final Answer: C

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