# Introduction

This module focuses on mathematical content in the lessons. Sometimes the questions posed will deal with the same level of mathematical content knowledge as students; other times the questions posed will deal with a higher level of content knowledge, appropriate for teachers.

Some Areas in Rate Problems Students Find Challenging:

• Multiple unit types
• Multiple steps
• Selecting which formula to use.
• Concepts of time and distance.
• Concept of a rate

The questions in this module focus on the following topics:

• Using the relationship D = RT in applied situations, with emphasis on non-matching units;
• Interpreting rate relationships in situations involving quantities other than physical distance; and
• Interpreting D = RT relationships graphically as well as algebraically.

The focus CAHSEE release question for this unit is as follows:

Chris drove 100 kilometers from San Francisco to Santa Cruz in 2 hours and 30 minutes. What computation will give Chris' average speed, in kilometers per hour?

A. Divide100 by 2.5
B. Divide 100 by 2.3
C. Multiply 100 by 2.5
D. Multiply 100 by 2.3