1. **Problem statement:** A merchant marks up everything by 40%. Find the retail price of an item costing the merchant 15. 2. **Formula:** Retail price = Cost price + Markup Markup = Cost price \times Markup rate 3. **Calculate the markup:** $$\text{Markup} = 15 \times 0.40 = 6$$ 4. **Calculate the retail price:** $$\text{Retail price} = 15 + 6 = 21$$ 5. **Answer:** The retail price of the item is 21. Note: The second question is incomplete and thus not solved here.