Peder currently works 40 hours a week

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Peder currently works 40 hours a week

by guerrero » Tue Aug 27, 2013 12:51 am
Peder currently works 40 hours a week. If his hourly wage went up by $3, how many fewer hours could he work and still earn the same weekly income as he did before the increase?

A)His weekly income is currently $600.
B)The increase of $3 is a 20 percent increase over his currently hourly wage.
Source: — Data Sufficiency |

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by Brent@GMATPrepNow » Tue Aug 27, 2013 7:10 am
guerrero wrote:Peder currently works 40 hours a week. If his hourly wage went up by $3, how many fewer hours could he work and still earn the same weekly income as he did before the increase?

A)His weekly income is currently $600.
B)The increase of $3 is a 20 percent increase over his currently hourly wage.
This question has a great takeaway: DO NOT PERFORM UNNECESSARY CALCULATIONS. Remember that DS question require to determine whether or not we have enough (sufficient) information to answer the target question. WE NEED NOT ACTUALLY ANSWER THE TARGET QUESTION.


Target question: How many fewer hours could Peder work and still earn the same weekly income as he did before the increase?

IMPORTANT: To answer the target question, all we need to do is determine Peder's current rate of pay (salary). Once we know his current salary, we can answer the target question.

Statement 1: His weekly income is currently $600.
Perfect!
Notice that we COULD use this information to determine Peder's current hourly wage ($600/40 = $15/hour), and then we COULD determine Peder's rate of pay after the $3 increase ($18/hour) and then we COULD determine how many fewer hours Peder needs to work to make $600 (40 - 600/18 = 6 2/3 fewer hours) .
HOWEVER, we'd never perform all of those calculations, because our only job here is to determine whether or not the statements are sufficient.
So, since we COULD answer the target question with certainty, statement 1 is SUFFICIENT


Statement 2: The increase of $3 is a 20 percent increase over his currently hourly wage.
In other words, $3 = 20% of Peder's current hourly rate of pay
Since we COULD use this to determine Peder's current hourly rate of pay ($15/hour), then we COULD eventually answer the target question with certainty.
So, statement 2 is SUFFICIENT

Answer = D

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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