A ratio is a comparison of two numbers or measurements. The objects being compared are called the terms of the ratio. If the two terms are different units it is called a rate.
For example, if a 12-ounce coke costs 84¢, the rate is 84¢ for 12 ounces. The ratio would be 84¢/12oz or 84¢:12oz. Both expressions mean you pay 84¢ for 12 ounces. A unit rate is when the quantities are expressed as a ratio of 1. This would mean that 1 ounce is worth 7¢.
Solved Examples:
1. Mari picked 100 oranges from 20 trees. What is the unit rate?
100 oranges or 100 oranges:20 trees
20 trees
When simplified, both equal 5.
Answer: Mari picked 5 oranges per tree.
2. A salesclerk gets 225 calls for 5 sales. What is the amount of calls he gets for each sale?
225 calls or 225 calls:5 sales
5 sales
When simplified, both equal 45.
Answer: The salesclerk gets 45 calls per sale.
3. Alice drives 224 miles in 2 hours. How many miles does she drive per hour?
224 miles or 224 miles:2 hours
2 hours
When simplified, both equal 112.
Answer: Alice drives 112 miles per hour.
4. A pack of 50 pencils costs $10. What is the cost of each pencil?
$10 or $10:50 pencils
50 pencils
When simplified, both equal $0.20 or 20¢.
Answer: Each pencil costs $0.20 or 20¢.
Sample Problems:
1. Johnny’s Cleaning Service charges $400 to clean 8 offices. What is the company’s price for cleaning a single office?
2. Alyssa walks 4938 steps in 2 hours. How many steps does she walk per hour?
3. The average human blinks 600 times in 30 minutes. How many times does one blink in one minute?
4. A pack of 6 coke cans has 1200 calories. How many calories does each can have
