A purchaser paid \( \$ 1,539,13 \) for a computer system that originally cost 81,050 , If the markup was \( 21 \% \) of the \( 81,539,13 \) selling price, then what is the percent markup based on cost? (Round to the nearest tenth percent) select one: a a, \( 26.6 \% \) b, \( 81.0 \% \) c, \( 79.7 \% \) d. \( 35.7 \% \)

Let's break down the problem step by step to find the percent markup based on cost. ### Given: 1. **Selling Price (S):** \$1,539.13 2. **Original Cost (C):** \$81,050 3. **Markup Percentage:** 21% of the selling price ### Understanding the Markup: - The markup is **21% of the selling price**. This can be expressed as: \[ \text{Markup} = 0.21 \times S \] ### Relationship Between Selling Price and Cost: - The selling price is the sum of the original cost and the markup: \[ S = C + \text{Markup} \] - Substituting the markup expression: \[ S = C + 0.21 \times S \] - Rearranging to solve for \( S \): \[ S - 0.21 \times S = C \\ 0.79 \times S = C \\ S = \frac{C}{0.79} \] ### Calculating the Markup Based on Cost: - Now, substitute \( S \) back into the markup equation: \[ \text{Markup} = 0.21 \times \frac{C}{0.79} \approx 0.2658 \times C \] - To find the **percent markup based on cost**, multiply by 100: \[ \text{Percent Markup} \approx 26.6\% \] ### **Answer:** **a. 26.6 %**