ch. 5 percent. ch. 5-1 ratios and percents vocabulary percent: a ratio that compares a number to 100
TRANSCRIPT
Write ratios and fractions as percents1/5
1 x 20 = 20
5 x 20 100
So, 1 out of 5 equals to 20%
Can you turn “3 out of 5 people” to a percent?
60%
Write ratios and fractions as percents
1/200
1 2 = 0.5
200 2 100
So, 1 out of 200 equals to 0.5%
Can you turn ¼ to a percent?
25%
Write percents as fraction
paper30%
Plastic 24%
Food & Yard Waste 11%
Other trash 35%
Paper: 30% = 30 100= 3 10Can you write plastic, food
% yard waste, and other trash as fraction?
Write percents as fraction
paper30%
Plastic 24%
Food & Yard Waste 11%
Other trash 35%
Plastic: 24%
= 24
100
= 6
25
Write percents as fraction
paper30%
Plastic 24%
Food & Yard Waste 11%
Other trash 35%
Food & yard waste:
11%
= 11
100
Write percents as fraction
paper30%
Plastic 24%
Food & Yard Waste 11%
Other trash 35%
Other trash:
35%
= 35
100
= 7
20
Ch. 5-2 Fractions, Decimals, and Percents
Write % as decimal
To write a percent as a decimal, divide by 100 and remove the percent symbol
39% =39 100 =39 x 10ˉ² = 39. =0.39 Can you write 35% &
115% as decimal? 0.35 & 1.15
Ch. 5-2 Fractions, Decimals, and Percents
Write decimal as %
To write a decimal as a percent, multiply by 100 and add the percent symbol
0.2 =0.2 x 100 =0.2 x 10² = .2 =20% Can you write 1.66 as
percent? 166%
Ch. 5-2 Fractions, Decimals, and PercentsWrite fraction as %To write a fraction as a
percent, there are two methods:
Method 1Change the fraction to
decimal, then multiply by 100 and add the percent symbol
3/8 = 3 8 0.375 =0.375 x 100 =0.375 x 10² =0.375 = 37.5% Change 3/16 to
percent 18.75%
Ch. 5-2 Fractions, Decimals, and Percents
Write fraction as %
To write a fraction as a percent, there are two methods:
Method 2
Use a proportion
3 = x%
8 100
300 = 8x
300 = 8x
8 8
x = 37.5
So, 3/8 equals to 37.5%
Change 1/9 to percent
11.1%
Ch. 5-3 Percent Proportion
Percent Proportion:
Part = %
Base 100
Use percent proportion to find the percent
22 is what % of 110?
22 = p%
110 100
22 * 100 =110*p
2200 = 110p
2200 = 110p
110 110
20 = p
So, 22 is 20% of 110.
Ch. 5-3 Percent Proportion
Percent Proportion:
Part = %
Base 100
Use percent proportion to find the percent
32 is what % of 125?
32 = p%
125 100
32 * 100 =125*p
3200 = 125p
3200 = 125p
125 125
25.6 = p
So, 32 is 25.6% of 125.
Ch. 5-3 Percent Proportion
Use equation to find the part.
What number => n
Is => equal
Of => multiply
What number is 80% of 500?
n = 80% x 500
n = 0.8 x 500
n = 400
So, 400 is 80% of 500.
What number is 25.5% of 210?
53.55%
Ch. 5-3 Percent Proportion
Use equation to find the base.
7 is 70% of what number?
7 = 70% x n
7 = 0.7 x n
7 = 0.7n
7 = 0.7n
0.7 0.7
10 = n
So, 7 is 70% of 10.
12 is 25% of what number?
48
Ch. 5-7Vocabulary• Percent of change: a ratio that compares the
change in quantity to the original amount.• Percent of increase: when the new amount is
greater than the original• Percent of decrease: when the new amount is
less than the original• Markup: the increase in the price• Discount: when regular price is reduced
Ch. 5-7 Percent of change
Percent of change= amount of change original amount
Original: 12, new: 9= 12-9 12=0.25Percent of decrease is
25%Original: 5, new: 6, find
percent of change.20% increased.
Ch. 5-7 Percent of changeFind the selling price
Selling price = markup rate + cost
The cost of roller blades is $60, 35% markup, find the selling price.
Markup rate= $60 (0.35)= $21Selling price =$60+$21=$81
Ch. 5-7 Percent of changeFind the selling price
Selling price = markup rate + cost
Cost of jeans: $25, 45% markup, find the selling price.
Markup rate= $25 (0.45)= $11.25Selling price =$25+$11.25=$36.25
Ch. 5-7 Percent of change
Find the Markup Rate
Markup Rate
Selling price - cost
cost
Cost of jeans: $25, sell for $36.25, find the markup rate.
= 36.25-25
25
= 0.45
= 45%
The markup rate is 45%
Ch. 5-7 Percent of change
Find the Markup Rate
Markup Rate
Selling price - cost
cost
Find the markup rate on a $60 jacket that sells for $75.
= 75-60
60
= 0.25
= 25%
The markup rate is 25%
Ch. 5-7 Percent of changeFind the Sale Price
Sale PriceSelling price - discount
Snowskate: $95, 35% off, find the sale price
Amount of discount:=$95*35%=$33.25Sale prince:= $95-$33.25=$61.75The Sale price is $61.75
Ch. 5-7 Percent of changeFind the Sale Price
Sale PriceSelling price - discount
Television: $675.50, 35% off, find the sale price
Amount of discount:=$675.50*35%=$236.43 (round to the nearest
100th)
Sale prince:=$675.50-$236.43=$439.08The Sale price is $439.08
Ch. 5-8Vocabulary• Interest: the amount of money paid or earned
for the use of money. la cantidad de dinero pagado o ganado para el uso de dinero. (For example, you earn interest from your saving account, but you pay interest when you borrow money from bank. E.g. car loan, mortgage, etc…) (Por ejemplo, usted gana el interés de su cuenta de ahorro, pero usted paga el interés cuando usted pide dinero prestado del banco. Por ejemplo préstamo de coche, la hipoteca, etc…).
• Principal: the amount of money invested or borrowed. (la cantidad de dinero invertido o pedido prestaddo.)
Ch. 5-8 Simple Interest
I = prt
I = interest, p = principal, r = rate t = time (time in years)
(Tiempo en años)
*If months are given, you must change the time in years.
*Si meses son dados, usted debe cambiar el tiempo en años.
Example 1: Find the simple interest
Annie deposit $500 at a rate of 6.25% for 3 years.
I = prt
I = $500 x 0.0625 x 3
I = $31.25 x 3
I = $93.75
The simple interest is $93.75
Ch. 5-8 Simple Interest
Your turn:
I = prt I = interest, p = principal, r = rate t = time (time in years)
(Tiempo en años)
Find the simple interest.
$200 at 7.5% for 4 years.
I = $200 x 0.075 x 4
I = $15 x 4
I = $60
The simple interest is $60
What is the total amount?
=$200+$60 = $260
Ch. 5-8 Simple InterestExample 2: Find the total
amount Total amount = p + I
Find the total amount ofmoney in an accountwhere $95 is invested at7.5% for 8 months. *one year has 12 months,
8 months is 8/12 = 2/3 year
I = prtI = $95 x 0.075 x 2/3I = $4.75
The total amount:= p + I= $95 + $4.75= $99.75The total amount is $99.75
Ch. 5-8 Simple InterestYour turnFind the total amount: = p + I
Find the total amount ofmoney in an accountwhere $200 is investedat 8.5% for 9 months. *one year has 12 months,
9 months is 9/12 = 3/4 year
I = prt
I = $200 x 0.085 x 3/4
I = $12.75
The total amount:
= p + I
= $200 + $12.75
= $212.75The total amount is
$212.75
Ch. 5-8 Simple Interest
Find the Interest Rate: I = prt
Booker earned $1200 over the summer. He invested (invertido) the money in stocks. To his surprise, the stocks increased in value to $1,335 in only 9 months. Find the simple interest rate for the investment.
I = $1335 - $1200 = $135p = $1200t = 9/12 = 3/4
Ch. 5-8 Simple Interest
Your turn
Find the Interest Rate: I = prt
A $750 investment earned $540 in 6 years. Write an equation you can use to find the simple interest rate. Then find the simple interest rate.
I = $540
p = $750
t = 6