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Arithmetic Percents

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by datonman » Wed Nov 11, 2015 10:55 am
Guy's net income equals his gross income minus his deductions. By what percent did Guy's net income change on January 1, 1989, when both his gross income and his deductions increased?

(1) Guy's gross income increased by 4 percent on January 1, 1989.
(2) Guy's gross income increased by 15 percent on January 1, 1989.
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by Jim@StratusPrep » Wed Nov 11, 2015 11:51 am
With percents, you will often need to know the base to understand change. If you use Gross income as 100 and test scenarios where deductions are 1 and 99, you will get 2 different changes in net income.

This makes the answer E.


Also, Statement 2 should be the deductions increased by 15 percent.
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by ceilidh.erickson » Thu Nov 30, 2017 3:39 pm
datonman wrote:Guy's net income equals his gross income minus his deductions. By what percent did Guy's net income change on January 1, 1989, when both his gross income and his deductions increased?

(1) Guy's gross income increased by 4 percent on January 1, 1989.
(2) Guy's gross income increased by 15 percent on January 1, 1989.
Here are 3 much more thorough explanations:
https://www.beatthegmat.com/og2016-q69-t ... tml#770961
https://www.beatthegmat.com/og2016-q69-t ... tml#770964
https://www.beatthegmat.com/og2016-q69-t ... tml#770965
Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
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