1. Applications of Percent problems
4/22/2013
Review:
Applications of Percent problems

2. Ex. 1) A color laser printer marked originally priced at $699 goes on sale for 30% off. If Chris has already saved up $325, how much more money does he need to buy the printer at the sale price?
Find the discount.
Find the sale price.
Sale price = original – discount
Sale price = $699 - $209.70
Sale price = $489.30
Money needed = sale price – money saved
Money needed = $ $325
Money needed = $164.30
Find how much more money Chris needs.

3. Ex. 2) A bicycle helmet is priced at $18. 50
Ex. 2) A bicycle helmet is priced at $ If it is on sale for 10% off and there is 7% sales tax, how much will it cost after tax?
First, find the sale price at 10% off of the original price.
Next, find the sale price plus 7% tax.
Total cost = sale price + tax
Total cost = $ $1.17
Total cost = $17.82
Sale price = original – discount Sale price = $18.50 – $1.85 Sale price = $16.65

4. Ex. 3) All appliances at Bargain Outlet are marked down to 70% of the original price. Fred has a coupon for an additional 18% off of the sale price. If the original price of a microwave is $500, how much would Fred pay for the oven before tax?
First, find the price at 70% off the original price.
Next, find the price with the additional 18% off the sale price.
Final price = sale price – discount
Final price = $350 - $63
Final price = $287
The final price is the sale price minus the additional discount.

5. The total cost of the couch plus tax is $600 .
4/22/2013
Ex. 4) Bob offered the salesperson at Furniture Express $600 for a new couch. This offer included 8% sales tax. If the salesperson accepts the offer, what was the cost of couch to the nearest dollar?
The total cost of the couch plus tax is $600 .
Let x = the cost of the couch
The tax on the couch is 8% of the cost.
Total cost = cost of couch + tax
$600 = x x
$600 = 1.08x
$ = x
$556 ≈ x
To the nearest dollar, the couch costs $556.

6. Ex. 5) Between noon and 8:00 p. m
Ex. 5) Between noon and 8:00 p.m., the temperature dropped from 70o F to 35o F. What was the percent decrease in temperature between noon and 8:00 p.m.?
Remember, percent of change (increase or decrease) is a variation of the percent proportion.
There was a 50% decrease in temperature between noon and 8:00 p.m.

7. Percent error is another variation of the percent proportion.
Ex. 6) The radius of a circle was estimated at 15.6 cm. The actual radius was 15.3 cm. Find the percent error in the estimation to the nearest hundredth of a percent.
Percent error is another variation of the percent proportion.
The percent error of the estimation was 1.96%.

8. In 3 years, $130.50 would be earned in simple interest.
Ex. 7) What is the amount of simple interest on a principal of $580 invested at a rate of 7.5% for 3 years?
The simple interest formula is I = prt where
I = interest
P = principal, or the amount of money borrowed or invested
r = annual interest rate expressed as a decimal
t = time in years
In 3 years, $ would be earned in simple interest.