All ISEE Middle Level Quantitative Resources
Example Questions
Example Question #11 : How To Divide Fractions
is a positive number, and . Which is the greater quantity?
(a) The reciprocal of
(b) The reciprocal of
(b) is the greater quantity
(a) is the greater quantity
It is impossible to determine which quantity is the greater from the information given
(a) and (b) are equal
(a) is the greater quantity
.
The reciprocal of is therefore - that is, times the reciprocal of . The reciprocal of a positive number must be positive, and , so
The reciprocal of is the greater number.
Example Question #12 : Fractions
is a positive number. Which is the greater quantity?
(a) The reciprocal of
(b) The reciprocal of
(a) is the greater quantity
It is impossible to determine which is greater from the information given
(b) is the greater quantity
(a) and (b) are equal
It is impossible to determine which is greater from the information given
We examine two scenarios to demonstrate that the given information is insufficient.
Case 1:
The reciprocal of this is .
The reciprocal of this is .
, so has the greater reciprocal.
Case 2: .
The reciprocal of this is .
The reciprocal of this is .
, so has the greater reciprocal.
Example Question #13 : Fractions
is a negative number. Which is the greater quantity?
(a) The reciprocal of
(b) The reciprocal of
(b) is the greater quantity
(a) and (b) are equal
(a) is the greater quantity
It is impossible to determine which is greater from the information given
(b) is the greater quantity
is negative, so we will let , making positive. It follows that .
The reciprocal of is ;
the reciprocal of is .
and are both positive; , so , and . Therefore, the reciprocal of is the greater quantity.