What percentage profit did the man make when he bought a farm for $2400 and sold it for $2700?

To calculate the percentage gain from the sale of the farm, you can follow these steps:

1. Determine the cost price (CP) and selling price (SP):
   The man bought the farm for $2400 (CP) and sold it for $2700 (SP).
2. Calculate the gain:
   Gain can be calculated using the formula: Gain = Selling Price - Cost Price.
   Plugging in the values: Gain = $2700 - $2400 = $300.
3. Calculate the percentage gain:
   The formula for percentage gain is: Percentage Gain = (Gain / Cost Price) × 100.
   Substituting the values: Percentage Gain = ($300 / $2400) × 100.
4. Perform the calculation:
   Percentage Gain = 0.125 × 100 = 12.5%.

Therefore, the man made a 12.5% gain when he sold the farm.