1. **State the problem:** Calculate the retail price given the cost and mark-up percentage using the formula: $$\text{Retail Price} = \text{Cost} + (\text{Cost} \times \text{Mark-up \%})$$ 2. **Explain the formula:** The retail price is the original cost plus the additional amount added as a mark-up, which is a percentage of the cost. 3. **Calculate for Sunkist:** Mark-up = $78 \times 0.10 = 7.80$ Retail Price = $78 + 7.80 = 85.80$ 4. **Calculate for Tamarind Sweet:** Mark-up = $150 \times 0.50 = 75$ Retail Price = $150 + 75 = 225$ 5. **Calculate for Japan Vase:** Mark-up = $1349.50 \times 0.70 = 944.65$ Retail Price = $1349.50 + 944.65 = 2294.15$ 6. **Calculate for Colored Jeans:** Mark-up = $735.10 \times 0.20 = 147.02$ Retail Price = $735.10 + 147.02 = 882.12$ 7. **Calculate for Leather Shoes:** Mark-up = $3562.18 \times 0.15 = 534.33$ Retail Price = $3562.18 + 534.33 = 4096.51$ **Final answers:** - Sunkist: 85.80 - Tamarind Sweet: 225.00 - Japan Vase: 2294.15 - Colored Jeans: 882.12 - Leather Shoes: 4096.51