Example

Example: Solving a Word Problem about Books

Apply the seven-step problem-solving strategy to a word problem involving a comparative relationship between two unknown quantities.

Problem: Guillermo bought textbooks and notebooks at the bookstore. The number of textbooks was three more than twice the number of notebooks. He bought seven textbooks. How many notebooks did he buy?

Step 1. Read the problem. Step 2. Identify what you are looking for: How many notebooks did Guillermo buy? Step 3. Name what we are looking for: Let nn = the number of notebooks. Step 4. Translate: Restate the problem into an equation. The number of textbooks (77) was three more than twice the number of notebooks (2n+32n + 3), which translates to: 7=2n+37 = 2n + 3. Step 5. Solve the equation: Subtract 33 from both sides: 4=2n4 = 2n Divide by 22: 2=n2 = n Step 6. Check: If he bought 22 notebooks, is three more than twice that equal to 77? Twice 22 is 44, and 4+3=74 + 3 = 7. The total matches the 77 textbooks. Step 7. Answer: Guillermo bought 22 notebooks.

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Updated 2026-05-02

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