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### OG 115

by ssraf » Tue Jun 10, 2008 12:27 pm
Marys income is 60% more than Tims income, and Tims income is 40 less than Juans income. What percent of Juans income is Mary's income?

a) 124
b)120
c)96
d)80
e)64

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by aatech » Tue Jun 10, 2008 12:54 pm
Assuming Tim's income is 40 PERCENT less than Juan's

Suppose Juan income is 100

Tim's income = 60

Mary's income = 60 + (60*60/100) = 96

Mary's income is 96% of Juan's

Do confirm if my assumption is right

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by ssraf » Tue Jun 10, 2008 5:38 pm
yes thanks 96% is the right answer

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by exhilaration » Sun Jan 25, 2009 11:05 am
aatech wrote:Assuming Tim's income is 40 PERCENT less than Juan's

Suppose Juan income is 100

Tim's income = 60

Mary's income = 60 + (60*60/100) = 96

Mary's income is 96% of Juan's

Do confirm if my assumption is right
What if instead you assumed Tim's income is 100...

Tim's income = 100

Mary's income = 160

Juan = 140

Juan is then 12.5% less then Mary's income.

I know this approach is wrong because it does not lead to the OA but can you please explain where I made my mistake?

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by aroon7 » Sun Jan 25, 2009 11:21 am
i guess ssraf missed % after 40...
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by gaggleofgirls » Sun Jan 25, 2009 3:59 pm
What if instead you assumed Tim's income is 100...

Tim's income = 100

Mary's income = 160

Juan = 140

Juan is then 12.5% less then Mary's income.

I know this approach is wrong because it does not lead to the OA but can you please explain where I made my mistake?
Where you made your mistake is with Juan = 140. When Tim is 40% less than Juan, that does not mean that Juan = 140% of Tim.

Try plugging in numbers and you will see. If Juan makes $100 and Tim make 40% less than that, then Tim makes$100-$40 =$60.

If Tim makes $60 and Juan makes 140% of$60, then Juan makes $84 ($60 + 60*.4) = ($60 +$24) = $84. % don't work the way you were using them. So, Mary = 160%Tim Tim = %60Juan Therefore Mary = %160 (%60 Juan) 1.6 * .6 = .96 = 96% Answer is C -Carrie Master | Next Rank: 500 Posts Posts: 165 Joined: 24 Mar 2010 Thanked: 2 times Followed by:1 members by HPengineer » Fri Sep 10, 2010 5:08 pm I also tried to solve this using following values but could not find the correct answer. Can some one please explain what is the correct value of juan's income of Tim is 100? Tim's income = 100 Mary's income = 160 Juan = 140 GMAT Instructor Posts: 15532 Joined: 25 May 2010 Location: New York, NY Thanked: 13060 times Followed by:1897 members GMAT Score:790 by GMATGuruNY » Fri Sep 10, 2010 7:19 pm HPengineer wrote:I also tried to solve this using following values but could not find the correct answer. Can some one please explain what is the correct value of juan's income of Tim is 100? Tim's income = 100 Mary's income = 160 Juan = 140 If t = 100 and j = Juan's income, let's translate into math the statement Tim's income is 40% less than Juan's income: 100 = j - .4j (100 = Juan's income - 40% of Juan's income) 100 = .6j j = 100/.6 = 1000/6 = 500/3. Thus, if m = 160, then m/j = 160/(500/3) = 160 * 3/500 = 480/500 = 48/50 = 96/100 = 96%. Plugging in for Tim's income makes the math messy. This problem requires us to plug and chug: plug in a value for one unknown and use this value to determine the values of all the other unknowns in the problem. When you're plugging and chugging, think about the best place to start plugging in. Since this problem asks what percent of Juan's income is Mary's income, we should let j=100 so that the question becomes: what percent of 100 is Mary's income? This will be an easy question to answer: j = 100 t = 60 (40% less than Juan's income of 100) m = 96 (60% more than Tim's income of 60) So m/j = 96/100 = 96%. So much easier! The correct answer is C. Mitch Hunt Private Tutor for the GMAT and GRE [email protected] If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon. Available for tutoring in NYC and long-distance. For more information, please email me at [email protected]. Student Review #1 Student Review #2 Student Review #3 Senior | Next Rank: 100 Posts Posts: 31 Joined: 11 Aug 2012 by Poisson » Sun Nov 13, 2016 10:32 am HPengineer wrote:I also tried to solve this using following values but could not find the correct answer. Can some one please explain what is the correct value of juan's income of Tim is 100? Tim's income = 100 Mary's income = 160 Juan = 140 I thought I would share my work on this problem with others who might run into the same issues. I kept getting answer choice E until I worked through what I was doing wrong. Knowing how to translate this question correctly is key to arriving at the right answer. A proper translation of the question also provides insight into what variables you should plug in for. Previously, I've been told to start with the common element, which is why I initially picked Tim = 100. You can use T = 100 and still arrive at the answer, but it takes longer and may be prone to error. Let's work on translating the sentences: "Mary's income is 60% more than Tim's income" This means M = 1.6T. If the question says X is 60 percent more than Y, then X = 1Y + 0.6Y = 1.6Y If the question would have said X is 60 percent LESS THAN Y, then X = 1Y - 0.6Y = X = 0.4Y What's key here is not to confuse LESS THAN with PERCENT OF. 60 percent of Y = (60/100)(Y) which reduces to (3/5)(Y)or simply use (0.6)(Y) 60 percent less than Y = 0.4Y Next the question states "Tim's income is 40 less than Juan's income." Again, this means T = 1J - 0.4J = 0.6J Finally, it asks "What percent of Juans income is Mary's income?" Here's a formation that can be used: What percent of A is B? This means "Is B" / "Percent of A" x 100 Using this formation: "Is Mary's Income" / "Percent of Juan's Income" or M/J = ? Although Tim is the common element, you're solving for M/J, and plugging in 100 for J will make the math easier and save you some time. Let's just say T=100 Then M = 160 Next, T = J - 0.4J. Plug in your values: 100 = J - 0.4J. 100 = 0.6J. Divide both sides by 0.6. Move the decimals to the right to get 1000/6 = J. The target question is M/J = 160/(1000/6) = (160*6)/1000 = (16*6)/100 = 96% That's not terrible, but this could've been much easier if J= 100. J = 100 T = 60 M = (0.6*60) + 60 = 36+60 = 96 That's it. M=96% Finally, here's the wrong way to translate the sentences: "Tims income is 40 less than Juans income." If T = 100, the translation IS NOT 100 = 0.4J. That is 40 PERCENT OF Juan, NOT 40 percent LESS THAN Juan Remember, when the question asks for LESS THAN, you are subtracting that percentage from a base of 1 (Ex. x is 2 percent less than y = x = 1y - 0.2y = 0.98y) When the question asks for PERCENT OF, then you are multiplying values: 30% of 70 = (0.3)(70) = 21 I hope this helps! Senior | Next Rank: 100 Posts Posts: 31 Joined: 11 Aug 2012 by Poisson » Sun Nov 13, 2016 10:35 am Poisson wrote: HPengineer wrote:I also tried to solve this using following values but could not find the correct answer. Can some one please explain what is the correct value of juan's income of Tim is 100? Tim's income = 100 Mary's income = 160 Juan = 140 I thought I would share my work on this problem with others who might run into the same issues. I kept getting answer choice E until I worked through what I was doing wrong. Knowing how to translate this question correctly is key to arriving at the right answer. A proper translation of the question also provides insight into what variables you should plug in for. Previously, I've been told to start with the common element, which is why I initially picked Tim = 100. You can use T = 100 and still arrive at the answer, but it takes longer and may be prone to error. Let's work on translating the sentences: "Mary's income is 60% more than Tim's income" This means M = 1.6T. If the question says X is 60 percent more than Y, then X = 1Y + 0.6Y = 1.6Y If the question would have said X is 60 percent LESS THAN Y, then X = 1Y - 0.6Y = X = 0.4Y What's key here is not to confuse LESS THAN with PERCENT OF. 60 percent of Y = (60/100)(Y) which reduces to (3/5)(Y)or simply use (0.6)(Y) 60 percent less than Y = 0.4Y Next the question states "Tim's income is 40 less than Juan's income." Again, this means T = 1J - 0.4J = 0.6J Finally, it asks "What percent of Juans income is Mary's income?" Here's a formation that can be used: What percent of A is B? This means ("Is B" / "Percent of A") x 100 Using this formation: "Is Mary's Income" / "Percent of Juan's Income" or M/J = ? Although Tim is the common element, you're solving for M/J, and plugging in 100 for J will make the math easier and save you some time. Let's just say T=100 Then M = 160 Next, T = J - 0.4J. Plug in your values: 100 = J - 0.4J. 100 = 0.6J. Divide both sides by 0.6. Move the decimals to the right to get 1000/6 = J. The target question is M/J = 160/(1000/6) = (160*6)/1000 = (16*6)/100 = 96% That's not terrible, but this could've been much easier if J= 100. J = 100 T = 60 M = (0.6*60) + 60 = 36+60 = 96 That's it. M=96% Finally, here's the wrong way to translate the sentences: "Tims income is 40 less than Juans income." If T = 100, the translation IS NOT 100 = 0.4J. That is 40 PERCENT OF Juan, NOT 40 percent LESS THAN Juan Remember, when the question asks for LESS THAN, you are subtracting that percentage from a base of 1 (Ex. x is 2 percent less than y = x = 1y - 0.2y = 0.98y) When the question asks for PERCENT OF, then you are multiplying values: 30% of 70 = (0.3)(70) = 21 I hope this helps! ### GMAT/MBA Expert GMAT Instructor Posts: 6106 Joined: 25 Apr 2015 Location: Los Angeles, CA Thanked: 43 times Followed by:24 members by [email protected] » Mon Nov 14, 2016 7:43 am ssraf wrote:Marys income is 60% more than Tims income, and Tims income is 40 less than Juans income. What percent of Juans income is Mary's income? a) 124 b)120 c)96 d)80 e)64 To solve this problem we create variables for the income of Mary, Tim, and Juan, and then set up some equations. T = Tim's income M = Mary's income J = Juan's income We are given that Mary's income is 60% more than Tim's. Thus, we can say: M = 1.6T We are also given that Tim's income is 40% less than Juan's income. So we can say: T = 0.6J We are asked to determine the percent of Juan's income that Mary's income is. For this we can set up the expression: M/J x 100% To complete this problem we must express Juan's income and Mary's income in terms of a common variable. That common variable is T. Thus, we have: M = 1.6T J = T/0.6 So finally we can substitute T/0.6 for J and 1.6T for M M/J x 100% (1.6T)/(T/0.6) x 100% (1.6T) x (0.6/T) x 100% The T's cancel and we have: 1.6 x 0.6 x 100% 0.96 x 100% = 96% Answer C For some students, an easier way to solve this is to use convenient numbers. If we "pretend" that Juan's income is J =$100, and Tim's income is 40% less than Juan's, then Tim's income is: 100 - (100)(.40) = $60. We also are told that Mary's income is 60% more than Tim's: 60 + (60)(.60) = 60 + 36 =$96.

Now we can easily determine the percent of Juan's income that Mary's income represents: (96/100) x 100% = 96%.

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by [email protected] » Mon Nov 14, 2016 7:46 am
Mary's income is 60 percent more than Tim's income, and Tim's income is 40 percent less than Juan's income. What percent of Juan's income is Mary's income?

A) 124%
B) 120%
C) 96%
D) 80%
E) 64%
I suggest that we choose some nice values that meet the given conditions.

Tim's income is 40 percent LESS THAN Juan's income.
Let Juan's income = $100 40% of$100 = $40 This means Tim's income =$100 - $40 =$60

Mary's income is 60 percent MORE THAN Tim's income
60% of $60 =$36
So Mary's income = $60+$36 = $96 What percent of Juan's income is Mary's income? Juan's income =$100
Mary's income = \$96

So, Mary's income is [spoiler]96%[/spoiler] of Juan's income