**Finding percent increase and decrease :**

Percents can be used to describe how an amount changes. The formula given below can be used to find how an amount changes in terms of percentage.

The change may be an increase or a decrease.

Percent increase describes how much a quantity increases in comparison tothe original amount.

Percent decrease describes how much a quantity decreases in comparison to the original amount.

**Example 1 : **

What is the percent increase from $5 to $8 ?

**Solution :**

**Step 1 :**

Find the amount of change.

Amount of change = Greater value - Lesser value

= 8 - 5

= 3

**Step 2 : **

Percentage change is

= (Amount of change / Original amount) x 100 %

= (3 / 5) x 100%

= 0.6 x 100 %

= 60 %

Hence, the percent increase from $5 to $8 is 60%.

Let us look at the next example on "Finding percent increase and decrease"

**Example 2 : **

Amber got a raise, and her hourly wage increased from $8 to $9.50. What is the percent increase?

**Solution :**

**Step 1 :**

Find the amount of change.

Amount of change = Greater value - Lesser value

= 9.50 - 8.00

= 1.50

**Step 2 : **

Find the percent increase. Round to the nearest percent.

Percentage change is

= (Amount of change / Original amount) x 100 %

= (1.50 / 8.00) x 100%

= 0.1875 x 100 %

= 18.75 %

**≃ **19 %

Hence, Amber's hourly wage is increased by 19%.

Let us look at the next example on "Finding percent increase and decrease"

**Example 3 : **

The price of a pair of shoes increases from $52 to $64. What is the percent increase to the nearest percent?

**Solution :**

**Step 1 :**

Find the amount of change.

Amount of change = Greater value - Lesser value

= 64 - 52

= 12

**Step 2 : **

Find the percent increase. Round to the nearest percent.

Percentage change is

= (Amount of change / Original amount) x 100 %

= (12 / 52) x 100%

= 0.2307 x 100 %

= 23.07 %

**≃ **23 %

Hence, the price of a pair of shoes increased by 23%.

Let us look at the next example on "Finding percent increase and decrease"

**Example 4 : **

In a class, students strength has been increased from 20 to 30. What percent of strength is increased ?

**Solution :**

**Step 1 :**

Find the amount of change.

Amount of change = Greater value - Lesser value

= 30 - 20

= 10

**Step 2 : **

Find the percent increase. Round to the nearest percent.

Percentage change is

= (Amount of change / Original amount) x 100 %

= (10 / 20) x 100%

= 0.5 x 100 %

= 50 %

Hence, the strength is increased by 50%.

Let us look at the next example on "Finding percent increase and decrease"

**Example 5 : **

Mr. David monthly salary is revised from $2500 to $2600. What percentage is the salary increased ?

**Solution :**

**Step 1 :**

Find the amount of change.

Amount of change = Greater value - Lesser value

= 2600 - 2500

= 100

**Step 2 : **

Find the percent increase. Round to the nearest percent.

Percentage change is

= (Amount of change / Original amount) x 100 %

= (100 / 2500) x 100%

= 0.04 x 100 %

= 4 %

Hence, David's monthly salary is increased by 4%.

Let us look at the next example on "Finding percent increase and decrease"

**Example 6 : **

What is the percent decrease from $80 to $64 ?

**Solution :**

**Step 1 :**

Find the amount of change.

Amount of change = Greater value - Lesser value

= 80 - 64

= 16

**Step 2 : **

Percentage change is

= (Amount of change / Original amount) x 100 %

= (16 / 80) x 100%

= 0.2 x 100 %

= 20 %

Hence, the percent decrease from $80 to $64 is 20%.

Let us look at the next example on "Finding percent increase and decrease"

**Example 7 : **

David moved from a house that is 89 miles away from his workplace to a house that is 51 miles away from his workplace. What is the percent decrease in the distance from his home to his workplace ?

**Solution :**

**Step 1 :**

Find the amount of change.

Amount of change = Greater value - Lesser value

= 89 - 51

= 38

**Step 2 : **

Find the percent decrease. Round to the nearest percent.

Percentage change is

= (Amount of change / Original amount) x 100 %

= (38 / 89) x 100%

= 0.427 x 100 %

= 42.7 %

**≃ **43 %

Hence, the percent decrease in the distance from his home to his workplace is 43%.

Let us look at the next example on "Finding percent increase and decrease"

**Example 8 : **

The number of students in a chess club decreased from 18 to 12. Whatis the percent decrease ? Round to the nearest percent.

**Solution :**

**Step 1 :**

Find the amount of change.

Amount of change = Greater value - Lesser value

= 18 - 12

= 6

**Step 2 : **

Find the percent decrease. Round to the nearest percent.

Percentage change is

= (Amount of change / Original amount) x 100 %

= (6 / 18) x 100%

= 0.3333 x 100 %

= 33.33%

**≃ **33 %

Hence, the strength is decreased by 33%.

Let us look at the next example on "Finding percent increase and decrease"

**Example 9 : **

Officer Brimberry wrote 16 tickets for traffic violations last week, but only 10 tickets this week. What is the percent decrease ?

**Solution :**

**Step 1 :**

Find the amount of change.

Amount of change = Greater value - Lesser value

= 16 - 10

= 6

**Step 2 : **

Find the percent decrease. Round to the nearest percent.

Percentage change is

= (Amount of change / Original amount) x 100 %

= (6 / 16) x 100%

= 0.375 x 100 %

= 37.5 %

**≃ **38 %

Hence, the percentage decrease is 38%.

Let us look at the next example on "Finding percent increase and decrease"

**Example 10 : **

Over the summer, Jackie played video games 3 hours per day. When school began in the fall, she was only allowed to play video games for half an hour per day. What is the percent decrease? Round to the nearest percent

**Solution :**

**Step 1 :**

Find the amount of change.

Amount of change = Greater value - Lesser value

= 3 - 0.5

= 2.5

**Step 2 : **

Find the percent decrease. Round to the nearest percent.

Percentage change is

= (Amount of change / Original amount) x 100 %

= (2.5 / 3) x 100 %

= 0.8333 x 100%

= 83.33 %

**≃ **83 %

Hence, the percentage decrease is 83%.

After having gone through the stuff given above, we hope that the students would have understood "Finding percent increase and decrease".

Apart from the stuff given above, if you want to know more about "Finding percent change", please click here

Apart from the stuff given in this section, if you need any other stuff in math, please use our google custom search here.

HTML Comment Box is loading comments...

**WORD PROBLEMS**

**HCF and LCM word problems**

**Word problems on simple equations **

**Word problems on linear equations **

**Word problems on quadratic equations**

**Area and perimeter word problems**

**Word problems on direct variation and inverse variation **

**Word problems on comparing rates**

**Converting customary units word problems **

**Converting metric units word problems**

**Word problems on simple interest**

**Word problems on compound interest**

**Word problems on types of angles **

**Complementary and supplementary angles word problems**

**Markup and markdown word problems **

**Word problems on mixed fractrions**

**One step equation word problems**

**Linear inequalities word problems**

**Ratio and proportion word problems**

**Word problems on sets and venn diagrams**

**Pythagorean theorem word problems**

**Percent of a number word problems**

**Word problems on constant speed**

**Word problems on average speed **

**Word problems on sum of the angles of a triangle is 180 degree**

**OTHER TOPICS **

**Time, speed and distance shortcuts**

**Ratio and proportion shortcuts**

**Domain and range of rational functions**

**Domain and range of rational functions with holes**

**Graphing rational functions with holes**

**Converting repeating decimals in to fractions**

**Decimal representation of rational numbers**

**Finding square root using long division**

**L.C.M method to solve time and work problems**

**Translating the word problems in to algebraic expressions**

**Remainder when 2 power 256 is divided by 17**

**Remainder when 17 power 23 is divided by 16**

**Sum of all three digit numbers divisible by 6**

**Sum of all three digit numbers divisible by 7**

**Sum of all three digit numbers divisible by 8**

**Sum of all three digit numbers formed using 1, 3, 4**

**Sum of all three four digit numbers formed with non zero digits**