Transcript Sec. 1.1 – Sets of Numbers

College Algebra K/DC
Tuesday, 02 September 2014
• OBJECTIVE TSW work with percents.
• QUIZZES are graded.
• Bring batteries/battery money to me at the
beginning of the period.
• ASSIGNMENT DUE WEDNESDAY/THURSDAY
– WS Percents
QUIZ: Algebra Review
Form A
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
3
22
37/
15
15/ cups
4
13 1/3%
58 7/12 yds.
$853.02
98.6
126 min
23 1/3%
120 females
6 times
Form B
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
1
10
26/
15
15/ cups
8
20%
47 5/12 yds.
$733.32
98
136 min
32.35%
152 females
14 times
Percents
• Percent means per one hundred.
Ex: 21% means 21 out of one hundred
or 21/100.
• The word of means multiply.
The word is means equals.
Ex: What is 30% of 18?
x = 18(30/100)
x = 27/5 or 5.4
Percents
• When something involves a discount with a
“new” price and an “old” price, use the
relationship
original price - new price
original price
Ex:
A pair of jeans originally sold for
$34.99, but is discounted to
$26.99. What is the rate of
discount?
34.99 - 26.99
 0.2286367534...
34.99
 22.86%
Percents
Ex:
Walmart sells Mr. Coffee coffee makers
for $15.99. This is a 17% mark down
from the original price. What was the
original price?
x  15.99
 0.17
x
x  15.99
x
 0.17  x
x
x  15.99  0.17x
0.83x  15.99
15.99
x 
0.83
x  19.26506
x  $19.27
Percents
• To determine total cost of a sale, multiple
the tax rate by the cost of the item and add
it to the cost of the item.
Ex:
A new television costs $499.95.
The tax rate is 8.25%. What is the
total cost of the television?
499.95  0.0825  41.245875
499.95  41.25  $541.20
or
499.95 1.0825  $541.20
Percents
• To determine the retail price of an item
(before tax), do the opposite.
Ex:
Bill paid $177.52 for his new DVD player.
This amount includes the tax, which has a
rate of 8.25%. What is the retail (list)
price of the DVD player?
x  x  0.0825   177.52
x (1  0.0825)  177.52
1.0825x  177.52
x  163.9907621
x  $163.99
Assignment
• WS Percents
– Due tomorrow, 04 September 2013
• REMINDER: TEST on Monday.