In this section, we will go through the percentage problems that you can expect on GMAT.
Percentage means value per 100.
For e.g. If A is 40 percent of 1000 that means for every 100 value of B there are 40 values percent of B.
Hence for 1000 value of A,
The value of B = 1000 (40 / 100)
B = 10 * 40 = 400
To find the value, divide the percentage value by 100.
In above e.g.,
B = 40% of A
= (40/100) * A
To represents X is y% of Z,
X = y% of Z
X = (y/100) * Z
X = (percent/100) * Base
Now try another question,
Find the value A, if A is 30% higher than 200.
Make sure to notice the word higher, A is 30% higher than 200. That means A is 200 and plus 30% of 200. i.e.
A = 200 + 30% of 200
= 200 + (30 /100) * 200
= 200 + 3 * 20
= 200 + 60
A = 260
Now, let’s solve a GMAT question –
A store reported total sales of $385 million for February of this year. If the total sales for the same month last year was $320 million, approximately what was the percent increase in sales?
Suppose total sales in February of this year is S and total sales in February of last year is L.
S = 385
L = 320
Required value = approximate percentage increase in sales
Suppose the approximate percentage increase in sales is X then, (S-L) is X percentage of L.
S-L = X% of L
S-L= (X/100) * L
385-320 = (X/100) * 320
65 = (X) * 3.2
X = 65/3.2 20
Hence the current year’s total sales in February is approximately 20% higher than the last years sales in February. The correct answer is (C) 20%.