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Rates & Ratios
Proportions
Percents
Percent of Change
Simple Interests & Percent Applications
100
Write the rate as a unit rate: 168 students to 7 classes.
24 students to 1 class.
100
Does 3/4 = 15/20 form a proportion?
Yes!
100
22 is what percent of 121?
22 / 121 = x / 100 18.18%
100
Find the percent of change: Wendy bought a pair of shoes for $77.50 last year. Now they cost $94.55.
94.55 - 77.50 / 77.50 22% increase
100
Find the sale price: Original price: $56 Percent discount: 15%
$47.60
200
Which is the better buy? 3 donuts for $1.99 or a dozen donuts for $7.49?
3 donuts = $0.66/roll 12 donuts = $0.62/roll (Better Buy)
200
There are 30 students in a math class. Only 18 of the students are girls. What percentage of the students are girls?
18 girls / 30 students = x% / 100 x = 60%
200
What number is 156% of 208?
x / 208 = 156 / 100 x = 324.48
200
Find the percent error: Adam was given a 50 cm piece of string for an experiment. He accidentally measured it as 45 cm.
50 - 45 / 50 10% Error
200
Find the retail price: Wholesale price: $29 Percent markup: 105%
$59.45
300
What is the unit rate? 9856 hours worked, 4 employees.
2464 hours / 1 employee
300
The ratio used to determine how much larger or smaller a model will be.
What is a scale?
300
On your French test, you scored an 85%. You got 34 questions correct. How many questions were on the test?
34 / x = 85 / 100 x = 40 questions
300
Find the percent of change: The doctor saw 54 cases of the flu in February. In April he saw 12 cases.
54 - 12 / 54 77.78%
300
You order a pizza. The bill is $12.50. You give the delivery person a 10% tip. The sales tax is 6%. What is the total cost of the pizza?
Tip = $1.25 Tax = $0.75 Total = $14.50
400
Which is the better buy? 4 packages of soap for $4.32 or 3 packages of soap for $3.36?
4 packages = $1.08/package (Better Buy) 3 packages = $1.12/package
400
Two cities are 540 km apart. If the scale on the map is 2 cm to 50 km, how far apart are the cities on the map?
2 cm / 50 km = x cm / 540 km x = 21.6 cm
400
32 is 25% of what number?
32 / x = 25 / 100 x = 128
400
Find the percent error: Kayla measured the volume of her glass of water. She measured the volume of the 12 oz cup to be 14 oz.
14 - 12 / 12 16.6% Error
400
Find the amount of simple interest earned: Principle: $750 Annual Rate: 3.5% Time: 18 months
$39.38
500
A ratio comparing numbers with different units.
What is a rate?
500
Solve for y: 2.3/4.6 = y/6.2
y = 3.1
500
Drew has $360 in his savings account. He earns 3% interest each month. How much interest would he earn in 1 month?
x / 360 = 3 / 100 x = $10.80
500
Find the percent of change: Original amount: 25 New amount: 40
40 - 25 / 25 60% increase
500
How much money must you deposit into a savings account that has a 3% annual interest rate to earn $100 in 3 years?
$1,111.11