Sure! I can help you prepare for your Unit Test on Unit Rates and Proportions. Here are some key concepts, sample problems, and tips related to unit rates and proportions that might be useful for your study:
Key Concepts:
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Unit Rate: A unit rate is a rate that has a denominator of one. For example, if you travel 60 miles in 2 hours, the unit rate is 30 miles per hour (60 miles ÷ 2 hours).
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Proportion: A proportion is an equation that states that two ratios are equivalent. For example, if you have the ratio 1:2, it can be written as 1/2 = 2/4.
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Cross-Multiplication: When solving proportions, you can use cross-multiplication to find an unknown value. If you have a proportion \( a/b = c/d \), then \( ad = bc \).
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Finding Unit Rates: To determine a unit rate, divide the numerator by the denominator. For instance, if a package of 4 apples costs $2, the unit rate is $0.50 per apple (2 ÷ 4).
Sample Problems:
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Problem 1: If a car travels 180 miles in 3 hours, what is the car's unit rate in miles per hour? Solution: 180 miles ÷ 3 hours = 60 miles per hour.
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Problem 2: If 5 gallons of paint costs $75, what is the cost of paint per gallon? Solution: $75 ÷ 5 gallons = $15 per gallon.
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Problem 3: Solve the proportion \( \frac{3}{x} = \frac{12}{16} \). Solution: Cross-multiply: \( 3 \cdot 16 = 12 \cdot x \) → 48 = 12x → x = 4.
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Problem 4: If a recipe requires 2 cups of sugar for every 5 cups of flour, what is the unit ratio of sugar to flour? Solution: The ratio is 2 cups of sugar to 5 cups of flour or 2:5.
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Problem 5: A car uses 4 gallons of gasoline to travel 120 miles. What is the car’s fuel efficiency in miles per gallon? Solution: 120 miles ÷ 4 gallons = 30 miles per gallon.
Tips for the Test:
- Read Carefully: Make sure to thoroughly read each question and understand what is being asked.
- Show Your Work: When solving problems, write out each step. This can help you catch mistakes and also gives partial credit if you answer incorrectly.
- Check Your Units: When dealing with rates, always keep track of your units to ensure they are consistent.
- Practice: If you have practice problems or previous quizzes, review those to reinforce your understanding.
If you need help with specific problems or concepts, feel free to ask! Good luck on your test!