GMAT Question of the Day - Data Sufficiency - Percent Change
If the total revenue at Company K and Company M decreased by d% from 2001 to 2003 what is the value of d?
(1) In 2001 Company K earned 2,500,000 more revenue than Company M earned.
(2) In 2003 Company K earned 2,225,000 more revenue than Company M earned.
GMAT Question of the Day Solution
In this question you will end up with two equations and three variables. Unless there is some special "perfect fit" happening you will be unable to solve for d. There happens to be a perfect fit if you substitute in for k-m. Once you do that you'll just have one variable and one equation.
How to see the perfect fit? In GMAT tutoring I'm always suggesting that students slow down and map out the question. In this case, avoid doing the work in your head. Try to write out the equations. Simplify the equation if you can. Factor. Reduce. The equations may seem intimidating but at the end of the day these equations are pretty standard. If it is challenging to write out these equations then you should consider working a bit more on your algebra. The GMAT is a nuanced critical thinking exam but your fundamentals are still extremely important.