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

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

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% ?

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?

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.

+ = 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% 100% 50%

Step 4: Equation/Solution Take what you know from your picture/verbal equation and transform into an algebraic equation .30(10) + 1.00(x) = .50(10 + x) 3 + x = 5 + .5 x .5x = 2 x = 4 + = 10 ml (30%) x ml (100%) 10 +x ml (50%)

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.

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.

Thank You and Questions ANY SUGGESTIONS? QUESTIONS?