Hi All,
We're told that Jones has worked at Firm X TWICE as many years as Green, and Green has worked at Firm X four years LONGER than Smith. We're asked for the number of years that Green has worked at Firm X. This question can be approached in a couple of different ways, but there's a built-in Algebra 'shortcut' that we can take advantage of. From the given information, we can create a couple of equations - and that should get you thinking about "System Math" (re: 2 variables and 2 unique equations, 3 variables and 3 unique equations, etc.).
To start, we'll use the variables J, G and S for Jones, Green and Smith, respectively. We can then create 2 equations:
J = 2G
G = S + 4
We're asked to find the value of G. Right now, we have 3 variables, but just 2 equations. If we can get one more UNIQUE equation involving some combination of these three variables, then we'll have a System of equations - and can solve for all 3 variables.
(1) Jones has worked at Firm X 9 years longer than Smith.
With the information in Fact 1, we can create the following equation:
J = S + 9
We now have a third unique equation, so we could solve for all 3 variables - including G. The shortcut is that we don't actually have to do that math; having the necessary equations to do it proves that we COULD get the one value of G that exists to answer the question.
Fact 1 is SUFFICIENT
(2) Green has worked at Firm X 5 years less than Jones.
With the information in Fact 2, we can create the following equation:
G = J - 5
Again, we have a third unique equation, so we could solve for all 3 variables - including G. The shortcut is that we don't actually have to do that math; having the necessary equations to do it proves that we COULD get the one value of G that exists to answer the question.
Fact 2 is SUFFICIENT
Final Answer:
GMAT assassins aren't born, they're made,
Rich
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