# Percent Increase/Decrease

Percent Increase/Decrease

1. The price of an Instazoom camera increased from \$75 to \$90. Find the percent of increase in price.

Solution

To find the percent of increase or decrease.

First find the change and then divide the change by the original amount.

The change here is 15

The original amount is 75

15/75 is .2

.2 = 20%

The percent of increase is 20%

1. The number of students attending Sky High School increased from 1600 to 1800. What was the percent of increase?

Solution

To find the percent of increase or decrease.

First find the change and then divide the change by the original amount.

The change here is 200

The original amount is 1600

200/1600 is .125

.125 = 12.5%

The percent of increase is 12.5%

1. Because of improved technology, the time needed to manufacture an XYZ machine has fallen from 20 hours to 9 hours. Find the percent of decrease.

Solution

To find the percent of increase or decrease.

First find the change and then divide the change by the original amount.

The change here is 11

The original amount is 20

11/20 is .55

.55 = 55%

The percent of decrease is 55%

1. After two weeks on the Try-No-Meal Diet, Terry’s weight dropped from 60 kg to 54 kg. Find the percent of decrease.

Solution

To find the percent of increase or decrease.

First find the change and then divide the change by the original amount.

The change here is 6

The original amount is 60

6/60 is .1

.1 = 10%

The percent of decrease is 10%

1. During one year, the value of a diamond increased 25%. If the diamond was originally worth \$3000, what was it worth one year later?

Solution

In this problem multiply the original amount (3000) by 1.25

3000 times 1.25 = 3750

So 1 year later the diamond is worth \$3750

1. During June a car dealer sold 250 new cars. During July he sold 14% fewer cars. How many cars did he sell in July?

Solution

In this problem if he sold 14% fewer cars then he did sell 86%

So 250 times .86 = 215

So the car dealer sold 215 cars.

1. At the close of one business day, TNT stock was trading at \$40 per share. At the close of the next business day, the stock was trading at \$46 per share. Find the percent of increase.

Solution

To find the percent of increase or decrease.

First find the change and then divide the change by the original amount.

The change here is 6

The original amount is 40

6/40 is .15

.15 = 15%

The percent of increase is 15%

1. A \$150 bicycle is on sale at a 20% discount. If there is a 5% sales tax, how much does the bicycle cost in all?

Solution

In this problem if the bicycle is at a 20% discount then 80% of the price was kept.

150 times .80 = 120

120 times 1.05 = 126

So the price of the bicycle after the discount and after tax is \$126