More Percent Applications

By Jim Olsen, W.I.U.#P24

For mark-ups and mark-downs, percent remaining works well.

You *can* have percent change on percent data.

There are four numbers to pay attention to:1. Original amount (the “old”/“starting” amount before the

change)2. New amount (the “ending” amount after the change)3. Amount of change (the difference [subtract] between

original and new)4. Percent change (percent increase or decrease).

Recall for Percent Change

Situtations

The Two Useful Relationships

▲If an increase:Percent remaining = 100% + Percent change

▼If a decrease:Percent remaining = 100% - Percent change

amount of changePercent change

original amount

(Original amount)(Percent remaining) (New amount)

Mark-upsRetailers, in order to make money, take their cost of an item and increase this amount to get the retail price.

Percent remaining works well to get the retail price.

Example:If the cost of a pair of jeans from the manufacture is

$16.00 and the store marks up the price by 80%, what is the retail price?

(16)(180%) (New amount)(16)(180%) (16)(1.8) $28.80

Mark-downsRetailers, in order to attract customers (and get rid of extra inventory), take their retail price of an item and decrease this amount to get the sale price.

Percent remaining works well to get the sale price.

Example:If the regular price of a sweatshirt is $30.00 and the

store marks it down by 40%, what is the sale price?

(30)(60%) (New amount)(30)(60%) (30)(.6) $18.00

You can have percent change on percent data.Sometimes the original data is in percent form.When describing the change, the media will report either

• The number of percentage points of change, or• The percent change.

You can have percent change on percent data.

Example:

In August the percent of people collecting food stamps was 20% and in September it went up to 22%. Find (a) the number of percentage points of change, and (b) the percent change.

(a)The percent of people collecting food stamps went up by 2 percentage points.

(b)The percent increase in the percent of people collecting food stamps was a 10% increase.

You can have percent change on percent data.

Example:

In August the percent of people approving of the president was 80% and in September it went up to 82%. Find (a) the number of percentage points of change, and (b) the percent change.

(a)The percent of people approving of the president went up by 2 percentage points.

(b)The percent increase in the people approving of the president was a 2.5% increase.

Another example:

In 2008, 40% of the people in Polk County owned a Ford vehicle. In 2009, the percent of Ford owners in Polk County was 37%. Find (a) the number of percentage points of change, and (b) the percent change.

(a)The percent of people owning a Ford went down by 3 percentage points.

(b)The percent decrease in the people owning a Ford was a 7.5% decrease.

Closing Notes Remember

#P24

For mark-ups and mark-downs, percent remaining works well.

You *can* have percent change on percent data.

Last one…

This is Day 24 of 24.

I hope you enjoyed, and learned from, this 24 Percent Tweets.

Learnist board: http://bit.ly/13AGhZqWebpage: http://bit.ly/ZXLw0I

Dr. Olsen