Many PMP and CAPM candidates are not aware that lite knowledge of Basic Algebra can come in very handy on the test.
Some questions may supply you with the endresult of a formula, and expect you to work backwards using algebra to solve for the inputs.
Below is an EXAMPLE:
TEST TIP! 
“Balance the equation… to isolate the variable.” 
The example below shows how to solve for a variable, in this case: EAC.
1) First, balance the equation.
(In this example, by adding $300,000 to both sides of the equation)
2. Second, isolate the variable: EAC.
EXAMPLE: (Practice Test Question) 
Q. If the amount of money remaining to complete your project (Estimate To Complete, or ETC) is $700,000, and the amount of MONEY you have spent so far (Actual Cost, or AC) is $300,000, what is your revised forecast (Estimate At Completion, or EAC)? 
To solve, use the ETC formula:

Plug in the ETC and AC into the ETC formula:

And the trick (Algebra) is:Balance the equation to isolate EAC, by ADDING $300,000 to both sides:


–Note that this works of course for many formulas, not just EAC, and for other kinds of math, not just addition/subtraction as in this example. 
 For many more test tips, see my book: The Project Management Answer Book
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