# Ch. 5 Percent. Ch. 5-1 Ratios and Percents Vocabulary Percent: a ratio that compares a number to 100.

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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 percents 1/5 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 Paper: 30% = 30 100 = 3 10 Can you write plastic, food % yard waste, and other trash as fraction?

Write percents as fraction Plastic: 24% = 24 100 = 6 25

Write percents as fraction Food & yard waste: 11% = 11 100

Write percents as fraction 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 Percents Write fraction as % To write a fraction as a percent, there are two methods: Method 1 Change 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 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 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 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 0.7 10 = n So, 7 is 70% of 10. 12 is 25% of what number? 48

Ch. 5-7 Percent of change

Ch. 5-7 Vocabulary 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 =0.25 Percent of decrease is 25% Original: 5, new: 6, find percent of change. 20% increased.

Ch. 5-7 Percent of change Find 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) = \$21 Selling price =\$60+\$21 =\$81

Ch. 5-7 Percent of change Find the selling price Selling price = markup rate + cost Cost of jeans: \$25, 45% markup, find the selling price. Markup rate = \$25 (0.45) = \$11.25 Selling 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 change Find the Sale Price Sale Price Selling price - discount Snowskate: \$95, 35% off, find the sale price Amount of discount: =\$95*35% =\$33.25 Sale prince: = \$95-\$33.25 =\$61.75 The Sale price is \$61.75

Ch. 5-7 Percent of change Find the Sale Price Sale Price Selling price - discount Television: \$675.50, 35% off, find the sale price Amount of discount: =\$675.50*35% =\$236.43 (round to the nearest 100 th ) Sale prince: =\$675.50-\$236.43 =\$439.08 The Sale price is \$439.08

Ch. 5-8 Simple Interest

Ch. 5-8 Vocabulary 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 Interest Example 2: Find the total amount Total amount = p + I Find the total amount of money in an account where \$95 is invested at 7.5% for 8 months. *one year has 12 months, 8 months is 8/12 = 2/3 year I = prt I = \$95 x 0.075 x 2/3 I = \$4.75 The total amount: = p + I = \$95 + \$4.75 = \$99.75 The total amount is \$99.75

Ch. 5-8 Simple Interest Your turn Find the total amount: = p + I Find the total amount of money in an account where \$200 is invested at 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 = \$212.75 The 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 = \$135 p = \$1200 t = 9/12 = 3/4

I = prt 135 = 1200 x r x ¾ 135 = 900r 900 r = 0.15 (15%) The interest rate is 15%

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

I = prt 540 = 750 x r x 6 540 = 4500r 4500 r = 0.12 (12%) The interest rate is 12%

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