Carlos received a restaurant bill for $60. He decided to leave a tip of 15% of the bill amount. What...

1. TRANSLATE the problem information

• Given information:
  • Restaurant bill: \(\$60\)
  • Tip rate: \(15\%\) of the bill amount
  • Need to find: tip amount in dollars
• What this tells us: We need to calculate \(15\%\) of \(\$60\)

2. TRANSLATE percentage to decimal form

• Convert \(15\%\) to decimal: \(15\% = \frac{15}{100} = 0.15\)
• The word "of" means multiplication in mathematics
• So "\(15\%\) of \(\$60\)" becomes: \(0.15 \times \$60\)

3. SIMPLIFY by performing the calculation

• Tip \(= 0.15 \times \$60\)
• Tip \(= \$9.00\)

Answer: C) \(\$9.00\)

Why Students Usually Falter on This Problem

Most Common Error Path:

Conceptual confusion about percentage notation: Students may interpret "\(15\%\)" as literally meaning "\(\$15\)"

Instead of converting \(15\%\) to \(0.15\), they think the tip should simply be \(\$15\) because the problem says "\(15\%\)." This fundamental misunderstanding of percentage notation bypasses the entire calculation process.

This may lead them to select Choice E (\(\$15.00\))

Second Most Common Error:

Weak TRANSLATE skill in percentage conversion: Students may incorrectly convert \(15\%\) to the wrong decimal value

For example, they might use \(0.10\) (thinking of \(10\%\)) or \(0.075\) (thinking of \(7.5\%\)), or make errors in the percentage-to-decimal conversion process. Even with correct understanding that they need to multiply, the wrong decimal leads to wrong answers.

This may lead them to select Choice A (\(\$4.50\)) or Choice B (\(\$6.00\)) depending on the specific conversion error.

The Bottom Line:

This problem tests fundamental percentage literacy - the ability to convert percentages to decimals and understand that calculating "percent of" requires multiplication. Students who struggle often have gaps in these foundational percentage concepts rather than arithmetic difficulties.