Summary Percentage

Percentages: Basic Concepts
and Problem Types
Simplification of Decreasing and
Increasing Percentages

 Understanding the concept of percentages and how
they relate to fractions and decimals is crucial
 When dealing with percentage problems, it is important
to convert the percentages to decimals or fractions
 To calculate a decrease or increase in percentage, the
following formula can be used:
 Final Value = Original Value * (1 ±
Percentage/100)

Finding the Change in Value and Rate

 To find the change in value when the rate is increased
or decreased, use the formula:
 New Rate = Original Rate * (1 ± Percentage/100)
 To find the change in value when the rate is increased
or decreased, multiply the original value by the new
rate:
 New Value = Original Value * New Rate

Salary Problems and Expenditure Ratio

 When dealing with salary problems, it is important to
understand the relationship between the salary and the
taxes, deductions, or increases
 To calculate the final salary after taxes or deductions,
use the formula:
 Final Salary = Original Salary * (1 - Tax Rate)
 To calculate the expenditure ratio, use the formula:
 Expenditure Ratio = Expenditure / Income