Final answer:
To find the gain, subtract the cost price from the selling price. The trader gained ₦43.00.
Step-by-step explanation:
To calculate the gain, we need to find the cost price and the selling price of the tins of milk.
Given that there are 2 dozen tins of milk and the cost per dozen is ₦2.50, the total cost price is 2 x ₦2.50 = ₦5.00.
Each tin is sold for ₦2.00, so the selling price of 2 dozen tins is 2 x 12 x ₦2.00 = ₦48.00.
To find the gain, we subtract the cost price from the selling price: ₦48.00 - ₦5.00 = ₦43.00.
The trader gained ₦43.00.