Maya has $240 to spend on school supplies for the semester. She must buy 8 graphing calculators that cost $20...

1. TRANSLATE the problem information

• Given information:
  • Total budget: \(\$240\)
  • Must buy: 8 graphing calculators at \(\$20\) each
  • Want to buy: notebooks at \(\$5\) each
  • Find: maximum number of notebooks possible

2. INFER the solution approach

• This is a two-part budget problem:
  • First, we must account for required purchases (calculators)
  • Then, see what's possible with remaining money (notebooks)
• We need to work in sequence: required purchases first, then optional purchases

3. Calculate the cost of required calculators

• Calculator cost = \(8 \times \$20 = \$160\)

4. Find remaining budget

• Remaining money = \(\$240 - \$160 = \$80\)

5. SIMPLIFY to find maximum notebooks

• Number of notebooks = \(\$80 \div \$5 = 16\) notebooks

Answer: C (16)

Why Students Usually Falter on This Problem

Most Common Error Path:

Weak INFER reasoning: Students miss that this is a sequential budget problem and jump straight to dividing total budget by notebook cost.

They calculate: \(\$240 \div \$5 = 48\) notebooks, completely ignoring the required calculator purchase. This leads them to think Maya can buy 48 notebooks with her full budget.

This may lead them to select Choice D (48)

The Bottom Line:

The key challenge is recognizing that required purchases must be handled first before determining what's possible with remaining funds. Students who treat this as a simple division problem miss the multi-step budget logic.