Bell WorkAfter an increase in his weekly wage of 20% Joe has $450.What was his wage before the increase?

$450 is 120% of

Complete a number line with this information

0% 100% 120%

$450

$375

Percent of Increase and decrease

A percent change is an increase or decrease given as a percent of the original amount. Percent increase describes an amount that has grown and percent decrease describes an amount that has be reduced.

Finding Percent Increase and Decrease

Find each percent change. Tell whether it is a percent increase or decrease.

Movie tickets went from $8 to $10

= 0.25

= 25% Write the answer as a percent.

Simplify the numerator.Simplify the fraction.

$8 to $10 is an increase, so a change from 8 to 10 is a 25% increase.

Shoes went from $75 to $30

= 0.6

= 60%Write the answer as a percent.

Simplify the numerator.Simplify the fraction.

75 to 30 is a decrease, so a change from 75 to 30 is a 60% decrease.

Finding Percent Increase and Decrease

Find the percent change. Tell whether it is a percent increase or decrease.

You try

From 200 to 110

= 0.6

= 60% Write the answer as a percent.

Simplify the numerator.Simplify the fraction.

200 to 110 is an decrease, so a change from 200 to 110 is a 60% decrease.

Find each percent change. Tell whether it is a percent increase or decrease.

You try:

From 25 to 30

= 0.20

= 20% Write the answer as a percent.

Simplify the numerator.Simplify the fraction.

25 to 30 is an increase, so a change from 25 to 30 is a 20% increase.

Find each percent change. Tell whether it is a percent increase or decrease.

Finding Percent Increase and Decrease

A. Find the result when 12 is increased by 50%.

0.50(12) = 6 Find 50% of 12. This is the amount of increase.

12 + 6 =18 It is a percent increase, so add 6 to the original amount.

12 increased by 50% is 18.

B. Find the result when 55 is decreased by 60%.

0.60(55) = 33Find 60% of 55. This is the amount of decrease.

55 – 33 = 22 It is a percent decrease so subtract 33 from the the original amount.

55 decreased by 60% is 22.

You try:A. Find the result when 72 is increased by 25%.

0.25(72) = 18 Find 25% of 72. This is the amount of increase.

72 + 18 =90 It is a percent increase, so add 18 to the original amount.

72 increased by 25% is 90.B. Find the result when 10 is decreased by 40%.

0.40(10) = 4Find 40% of 10. This is the amount of decrease.

10 – 4 = 6 It is a percent decrease so subtract 4 from the the original amount.

10 decreased by 40% is 6.

Practice: