|
|
Percentages - February 10, 2004
The GMAT Sample Math question for the day is from the topic Percentages.
Question
The difference between the value of a number increased by 12.5% and the value of the original number decreased by 25% is 30. What is the original number?
A. 60
B. 80
C. 40
D. 120
E. 160
The correct choice is (B) and the correct answer is 80.
Explanatory Answer
Let the original number be x.
Let A be the value obtained when x is increased by 12.5%.
Therefore, A = x + 12.5% of x
Let B be the value obtained when x is decreased by 25%.
Therefore, B = x - 25% of x
The question states that A - B = 30
i.e., x + 12.5% of x - (x - 25% of x) = 30
x + 12.5% of x - x + 25% of x = 30
37.5% of x = 30
x =  = 80
|
|
|
