Marta has 7,500 pesos she will convert to US dollars using a currency exchange service. At this time, the currency...

1. TRANSLATE the problem information

• Given information:
  • Marta has 7,500 pesos to convert
  • Exchange rate: 1 peso = 0.075 US dollars
  • Service fee: 2% of the converted US dollar amount
  • Find: How many US dollars Marta receives after the fee

2. INFER the solution approach

• This is a two-step sequential process:
  • First, convert pesos to dollars using the exchange rate
  • Then, apply the service fee to the converted dollar amount
• Key insight: The fee is charged on the US dollar amount, not the peso amount

3. SIMPLIFY the currency conversion

• Convert pesos to US dollars:
  \(7,500 \times 0.075 = \$562.50\)

4. SIMPLIFY the fee calculation

• The service charges 2% fee, so Marta receives 98% of the converted amount:
  \(\$562.50 \times 0.98 = \$551.25\) (use calculator)

Answer: A. \(\$551.25\)

Why Students Usually Falter on This Problem

Most Common Error Path:

Weak INFER skill: Students fail to recognize that this is a two-step process and stop after the currency conversion without applying the service fee.

They convert 7,500 pesos to \(\$562.50\) and think they're done, not realizing they need to subtract the 2% fee from this amount.

This leads them to select Choice B (\(\$562.50\)).

Second Most Common Error:

Poor TRANSLATE reasoning: Students misunderstand how to apply the percentage fee, treating it as a discount on the peso amount rather than a fee on the converted dollar amount.

They might calculate something like \(7,500 \times 0.98 \times 0.075\), applying operations in the wrong order or to the wrong quantities.

This leads to confusion and incorrect calculations that don't match any sensible answer choice.

The Bottom Line:

Currency conversion problems with fees require careful attention to the sequence of operations. The key insight is recognizing that fees are typically applied to the converted amount, not the original amount, making this a multi-step process where order matters.