All ISEE Upper Level Quantitative Resources
Example Questions
Example Question #91 : How To Find The Solution To An Equation
A hat costs $70.80 after a 20% discount. How much did the hat cost before the discount?
It is impossible to tell from the information given.
Since $70.80 is the price after a 20% discount off the original price, it is 80% of that original price. The problem is equivalent to asking:
$70.80 is 80% of what amount?
Let  be the price before discount.
Example Question #92 : How To Find The Solution To An Equation
Which is the greater quantity?
(A)Â
(B)Â
(B) is greater
It is impossible to determine which is greater from the information given
(A) and (B) are equal
(A) is greater
(B) is greater
, soÂ
.
Substitute for  in the other equation:
Â
Â
, so (B) is greater.
Example Question #93 : How To Find The Solution To An Equation
A line includes the points  andÂ
. Which is the greater quantity?
(A) The -coordinate of theÂ
-intercept.
(B) The -coordinate of theÂ
-intercept.
It is impossible to determine which is greater from the information given
(A) and (B) are equal
(A) is greater
(B) is greater
(A) is greater
We can figure out the equation of the line as follows:
Set . Substitute in the slope formula.
The slope isÂ
In the slope-intercept formula, we setÂ
 and solve forÂ
:
The equation isÂ
The -intercept isÂ
. To find theÂ
-intercept, we substitute 0 forÂ
:
The -intercept isÂ
.Â
This makes (A), the -coordinate of theÂ
-intercept, greater.Â
Example Question #91 : How To Find The Solution To An Equation
Define  andÂ
.
What is the domain of the function  ?
 has as its domain the set of values ofÂ
 for which its radicand is nonnegative; that is,
 orÂ
Similarly,  has as its domain the set of values ofÂ
 for which its radicand is nonnegative; that is,
 orÂ
Â
The domain of the sum of two functions is the intersection of the domains of the two individual functions. This intersection isÂ
Example Question #91 : Equations
Define  andÂ
.
Which is the greater quantity?
(A)Â
(B)Â
(A) and (B) are equal
(B) is greater
It is impossible to determine which is greater from the information given
(A) is greater
(A) and (B) are equal
Substitute  andÂ
 to determine the values of the respective expressions:
The expressions are equal.
Example Question #93 : How To Find The Solution To An Equation
For all real numbers  andÂ
, define an operationÂ
 as follows:
For which value of  is the expressionÂ
 undefined?
so
This expression is undefined if and only if the denominator is equal to 0, so
Example Question #92 : How To Find The Solution To An Equation
A line includes the points  andÂ
. What is theÂ
-intercept of this line (
-coordinate rounded to the nearest tenth)?
LetÂ
We calculate the slope as follows:
Apply the point-slope formula settingÂ
:
Set  to find theÂ
-coordinate of theÂ
-intercept:
The -intercept is (approximately at)Â
Example Question #95 : How To Find The Solution To An Equation
A line includes the points  andÂ
. What is theÂ
-intercept of this line?
LetÂ
We calculate the slope as follows:
Apply the point-slope formula settingÂ
Set  to find theÂ
-coordinate of the
-intercept:
The -intercept is Â
.
Example Question #91 : How To Find The Solution To An Equation
A line includes the points  andÂ
. Which of these is the slope of that line?
The correct answer is not among the other choices
LetÂ
We calculate the slope as follows:
Example Question #91 : Equations
For all real numbers  andÂ
, define an operationÂ
 as follows:
Let  be a positive number. Then which is the greater quantity?
(A)Â
(A)Â
It is impossible to determine which is greater from the information given
(B) is greater
(A) and (B) are equal
(A) is greater
(B) is greater
Substitute each pair of expressions:
We can compare these fractions by writing them with a common denominator:
 regardless of the value ofÂ
, Â making (B) greater.
All ISEE Upper Level Quantitative Resources
