Ch. 5 Percent. Ch. 5-1 Ratios and Percents Vocabulary Percent: a ratio that compares a number to...

Ch. 5 Percent

Ch. 5-1 Ratios and Percents

Vocabulary• Percent: a ratio that compares a number

to 100.

Write ratios as percents

Ratio 27 out of 100

= 27

100

=27%

Can you turn 32 out of 100 as percent?

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?


paper30%

Plastic 24%


Other trash 35%

Plastic: 24%

= 24

100

= 6

25


paper30%

Plastic 24%


Other trash 35%

Food & yard waste:

11%

= 11

100


paper30%

Plastic 24%


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


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%


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.


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.


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%


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. 5-7 Percent of change

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


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


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%


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. 5-8 Simple Interest

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.)


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


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


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

I = prt

135 = 1200 x r x ¾

135 = 900r

135 = 900r

900 900

r = 0.15 (15%)

The interest rate is 15%


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

I = prt

540 = 750 x r x 6

540 = 4500r

540 = 4500r

4500 4500

r = 0.12 (12%)

The interest rate is 12%

Ch. 5 Percent. Ch. 5-1 Ratios and Percents Vocabulary Percent: a ratio that compares a number to...

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