Bell Quiz

Objectives

• Solve rate and ratio problems.

Ratios and Rates

• A ratio is comparison of two quantities using division.

• A rate is a ratio that compares quantities

measured in different units.

• A unit rate is a rate whose denominator is 1. A unit price is the cost per unit.

Example 1Finding Unit Rate

Which is the better buy: 5 cans of tuna for $4.95 or 6 cans for $5.75?

Lesson Practice 1

Which is the better buy: 8 boxes for $4.96 or 5 boxes for $3.25?

Example 2Converting Rates

A Chemist raised the temperature of a liquid 45F in 1 minute. What is the amount in degrees Fahrenheit per second?

Lesson Practice 2

A bus driver drives at 30 miles per hour. What is the rate of the bus in miles per minute?

http://www.youtube.com/watch?v=Qhm7-LEBznk

Example 3Converting Rates

An engineer opens a valve that drains 60 gallons of water per minute from a tank. How many quarts were drained per second?

Lesson Practice 3

Jamie typed 20 pages of a document in 2 hours. How many pages did she type in 1 minute.

Proportions

• A proportion is an equation that shows two ratios are equal.

• The equation is a proportion.

Example 4Solving Proportions Using Cross Products

Lesson Practice 4

Example 5Solving Proportions Using Cross Products

Lesson Practice 5

Proportions

• Proportions are used to represent many real-world situations that require finding a missing value.

• Using the cross products is and efficient method for solving the proportions

Example 6Solving Multi-Step Proportions

The ratio of boys to girls in a math class is 3:2. The class has 25 students in all. How many boys and how many girls are in the class.

Lesson Practice 6

The ratio of blue chips to red chips in a bag is 5:7. The bag has 60 chips in all. How many blue chips and how many red chips are in the bag?

Example 7Solving Multi-Step Proportions

On the map, Albany to Jamestown measures 12.6cm, Jamestown to Springfield measures 9cm, and Springfield to Albany measures 4.75cm. what is the actual distance from Albany to Jamestown to Springfield and back to Albany?

Lesson Practice 7

A map shows a 5.5 inch distance between Orange City and Newtown, and a 3.75 inch distance from Newtown to Westville. The scale on the map is 1 inch:100 miles. What is the actual distance, if you drive from orange city via Newtown to Westville?

Example 8Applications: Trucking

Mr. Jackson drove a truck 300 miles in 6 hours. If he drives at a constant speed, how long will it take him to drive 450 miles?

Lesson Practice 8

If Jeff walks 4 miles in 48 minutes, how far can he walk in 72 minutes?