This is an example of a percent change question. The formula to solve this type of question is (new price - old cost / new cost). Solve the formula with the given values. 207.20-129.50/129.50 → 77.70/129.50 → 0.6. Turn the decimal into a percentage by multiply 0.6 * 100%. This gives us 60%. So, Amazon marked up this item by 60%.
~Good Luck!