All GRE Math Resources
Example Questions
Example Question #1 : How To Find The Reciprocal Of A Fraction
Carpenter A takes 45 hours to build a table. Carpenter B takes 30 hours. When they work together, how long will it take them to build a table?
Write their respective rates as fractions:
Carpenter A:
Carpenter B:
Add them together to find their combined rate. First find a common denominator. The smallest multiple of both 45 and 30 is 90:
Therefore, they take 18 hours to build a table together.
Example Question #2 : How To Find The Reciprocal Of A Fraction
What is the sum of the reciprocal of , the reciprocal of , the reciprocal of , and ?
None of the other answers
Begin by finding the reciprocal of , the reciprocal of , and the reciprocal of :
, ,
In order to add the four terms together, we will need to find a common denominator. Find the common denominator by multiplying the three different terms in the denominator (x, y, and z). Our common denominator will be . Put each term into terms of this common denominator:
Now, add each term together:
Look for the answer choice that matches this.
Example Question #52 : Fractions
Find the reciprocal of the following expression:
To find the reciprocal of a rational expression--any rational expression--all you need to do is flip the numerator and the denominator.
Therefore, the correct answer is:
You can check this by multiplying the two expressions together and ensuring that your answer is .
Example Question #2 : How To Find The Reciprocal Of A Fraction
Find the reciprocal of the following expression:
To find the reciprocal of any fraction, you merely need to invert the numerator and denominator.
In this case, first you have to convert the mixed number into a fraction:
Therefore, the answer is: