1. **Problem Statement:** A garden centre bought 40 lawnmowers at a cost of 216 each. 28 were sold for 270 each, and 12 were sold at a reduced price with a 15% mark-up. We need to find: (a) The mark-up percentage on a lawnmower sold for 270. 2. **Formula for Mark-up Percentage:** Mark-up % = \frac{Selling\ Price - Cost\ Price}{Cost\ Price} \times 100 3. **Calculate the mark-up for the lawnmower sold at 270:** Cost Price = 216 Selling Price = 270 Mark-up = 270 - 216 = 54 Mark-up % = \frac{54}{216} \times 100 4. **Simplify the fraction:** $$\frac{54}{216} = \frac{\cancel{54}^1}{\cancel{216}^4} = \frac{1}{4}$$ 5. **Calculate the percentage:** Mark-up % = \frac{1}{4} \times 100 = 25\% **Final answer:** The mark-up on a lawnmower sold for 270 is 25%.