All GMAT Math Resources
Example Questions
Example Question #1 : Understanding Absolute Value
A number is ten less than its own absolute value. What is this number?
No such number exists.
We can rewrite this as an equation, where is the number in question:
A nonnegative number is equal to its own absolute value, so if this number exists, it must be negative.
In thsi case, , and we can rewrite that equation as
This is the only number that fits the criterion.
Example Question #4 : Absolute Value
If , which of the following has the greatest absolute value?
Since , we know the following:
;
;
;
;
.
Also, we need to compare absolute values, so the greatest one must be either or .
We also know that when .
Thus, we know for sure that .
Example Question #5 : Absolute Value
Give all numbers that are twenty less than twice their own absolute value.
No such number exists.
We can rewrite this as an equation, where is the number in question:
If is nonnegative, then , and we can rewrite this as
Solve:
If is negative, then , and we can rewrite this as
The numbers have the given characteristics.
Example Question #3 : Absolute Value
Solve for in the absolute value equation
None of the other answers
None of the other answers
The correct answer is that there is no .
We start by adding to both sides giving
Then multiply both sides by .
Then divide both sides by
Now it is impossible to go any further. The absolute value of any quantity is always positive (or sometimes ). Here we have the absolute value of something equaling a negative number. That's never possible, hence there is no that makes this a true equation.
Example Question #4 : Absolute Value
Solve the following equation:
We start by isolating the expression with the absolute value:
becomes
So: or
We then solve the two equations above, which gives us 42 and 4 respectively.
So the solution is
Example Question #6 : Absolute Value
Solve the absolute value equation for .
The equation has no solution
None of the other answers.
We proceed as follows
(Start)
(Subtract 3 from both sides)
or (Quantity inside the absolute value can be positive or negative)
or (add five to both sides)
or
Another way to say this is
Example Question #6 : Absolute Value
Which of the following could be a value of ?
To solve an inequality we need to remember what the absolute value sign says about our expression. In this case it says that
can be written as
Of .
Rewriting this in one inequality we get:
From here we add one half to both sides .
Finally, we divide by two to isolate and solve for m.
Only is between -1.75 and 2.25
Example Question #444 : Algebra
The absolute value of negative seventeen is multiplied by a number that is three fewer than twelve. The resulting number is subtracted from negative six. What number is yielded at the end of this sequence of operations?
This is a problem where we need to use our translating skills. We are given a word problem and asked to solve it. To do so, we need to rewrite our word problem as an equation and then use arithmetic to find the answer. In these types of problems, the hardest step is usually translating correctly, so make sure to be meticulous and work step-by-step!
1)"The absolute value of negative seventeen": Recall that absolute value means that we will just change the sign to positive. Missing that will end up giving you the trap answer .
2)"is multiplied by a number which is three fewer than twelve." We need a number that is three fewer than twelve, so we need to subtract. Follow it up with multiplication and you get:
3)"The resulting number is subtracted from negative six." The key word here is "from"—make sure you aren't computing , which would result in another one of the trap answers!
The correct answer is .
Example Question #11 : Understanding Absolute Value
Solve .
or
or
or
Since we are solving an absolute value equation, , we must solve for both potential values of the equation:
1.)
2.)
Solving Equation 1:
Solving Equation 2:
Therefore, for , or .
Example Question #12 : Understanding Absolute Value
Solve .
or
or
or
Since we are solving an absolute value equation, , we must solve for both potential values of the equation:
1.)
2.)
Solving Equation 1:
Solving Equation 2:
Therefore, for , or .