Gmat prep Question

This topic has expert replies
Senior | Next Rank: 100 Posts
Posts: 37
Joined: Mon Jul 06, 2015 2:46 am

Gmat prep Question

by rakaisraka » Tue Aug 25, 2015 12:46 pm
Question - Before being simplified, the instructions for computing the income tax in country R were to add 2% of one's annual income to the average of 100 units of country R's currency and 1% of one's annual income. Which of the following represents the simplifed formula for computing the income tax , in country R'c currency , for a person in that country whose annual income is I.

A) 50 + I/200
B) 50 + 3I/100
C) 50 + I/40
D) 100 + I/50
E) 100 + 3I/100

Im not able to understand the question. Please help. Thanks
Source: — Problem Solving |

User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Tue Aug 25, 2015 12:48 pm
Before being simplified, the instructions for computing income tax in Country R were to add 2 percent of one's annual income to the average (arithmetic mean) of 100 units of Country R's currency and 1 percent of one's annual income. Which of the following represents the simplified formula for computing the income tax in Country R's currency, for a person in that country whose annual income is I?

(A) 50+I/200
(B) 50+3I/100
(C) 50+I/40
(D) 100+I/50
(E) 100+3I/100
Let I = 200 units of currency.
The tax is the SUM of two values: 2% of the income AND the average of 100 units of currency and 1% of the income.
2% of the income = .02(200) = 4.
The average of 100 units of currency and 1% of the income = (100 + .01(200)) / 2 = 102/2 = 51.
Tax = 4+51 = 55. This is our target.

Now plug I=200 into the answers to see which yield our target of 55.

Only answer choice C works:
50 + I/40 = 50 + 200/40 = 55.

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

Senior | Next Rank: 100 Posts
Posts: 37
Joined: Mon Jul 06, 2015 2:46 am

by rakaisraka » Tue Aug 25, 2015 1:01 pm
Thanks Mitch.

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10392
Joined: Sun Jun 23, 2013 6:38 pm
Location: Palo Alto, CA
Thanked: 2867 times
Followed by:511 members
GMAT Score:800

by [email protected] » Tue Aug 25, 2015 5:17 pm
Hi rakaisraka,

I'm a big fan of TESTing VALUES in these types of situations (the approach that Mitch used). You can also approach this question algebraically.

In certain Quant questions, you might find it easier to "convert" data from one format to another. While the answers are in "fraction format", you can very easily do the work with decimals, if you find that format easier.

Here we'd need to translate the given question into decimals:

J = one's income (I'm using "J" because an "I" looks like a 1)

2% of one's income = .02(J)

Avg of 100 units and 1% of one's income = (100 + .01(J)) / 2

Tax = .02(J) + 50 + .005(J)
Tax = .025(J) + 50
Tax = J(1/40) + 50

Final Answer: C

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Thu Nov 19, 2015 2:00 pm
Rich and Pitch have demonstrated the two methods (Algebraic and Input-Output) for solving a question type I call Variables in the Answer Choices.
If you'd like more information on these approaches, we have some free videos:
- Variables in the Answer Choices - https://www.gmatprepnow.com/module/gmat- ... /video/933
- Tips for the Algebraic Approach - https://www.gmatprepnow.com/module/gmat- ... /video/934
- Tips for the Input-Output Approach - https://www.gmatprepnow.com/module/gmat- ... /video/935

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image