1. Beth Marengo JSerra Catholic High School Math Department
WORD PROBLEMS
Beth Marengo
JSerra Catholic High School
Math Department

2. Overview: 6 Step Process
Step 1: What does the problem ask you to find?
Step 2: Let Statement
Step 3: What do you know?
Step 4: Algebraic Equation and Solution
Step 5: Check your answer
Step 6: Write a Sentence

3. Example Problem
A chemist has 10 milliliters of a solution that contains a 30% concentration of acid. How many milliliters of pure acid must be added in order to increase the concentration to 50% ?

4. STEP 1: What does the problem ask you to find?
A chemist has 10 milliliters of a solution that contains a 30% concentration of acid. How many milliliters of pure acid must be added in order to increase the concentration to 50% ?
The question is:
What amount of pure acid should the chemist add?

5. Let x = amount of pure acid to be added.
Step 2: Let Statement
This is the step where you identify your variable. Your variable should always refer to the unknown amounts from Step 1.
Let x = amount of pure acid to be added.

6. + = Step 3: What do you know? Students should do one of the following
Draw a picture
Write a verbal equation + =
Amount: 10 ml x ml 10 +x ml
Concentration: 30% % %

7. Step 4: Equation/Solution
Take what you know from your picture/verbal equation and transform into an algebraic equation
.30(10) (x) = .50(10 + x)
3 + x = x
.5x = 2
x = 4 + =
10 ml (30%) x ml (100%) x ml (50%)

8. Step 5: Check Answer
Ask the students, does your answer sound reasonable?
For example if we had reached a negative solution, this is not reasonable. You cannot add a negative amount of milliliters to increase concentration.
Students tend to overlook the fact that these are real life problems and require real life solutions.

9. THE CHEMIST NEEDS TO ADD 4 MILLILITERS OF PURE ACID TO THE SOLUTION.
Step 6: Write Sentence
Put your answer into a complete sentence.
This accomplishes two very important things.
Double checks that the answer is reasonable.
Ensures that you answered the question being asked.
THE CHEMIST NEEDS TO ADD 4 MILLILITERS OF PURE ACID TO THE SOLUTION.

10. Thank You and Questions
ANY SUGGESTIONS?
QUESTIONS?