To find the total cost of the apples, you can multiply the price per pound by the number of pounds picked.
The formula is:
\[ \text{Total cost} = \text{Price per pound} \times \text{Number of pounds} \]
Plugging in the values:
\[ \text{Total cost} = 1.40 , \text{dollars/pound} \times 2.5 , \text{pounds} \]
Calculating that:
\[ \text{Total cost} = 1.40 \times 2.5 = 3.50 \]
Therefore, the total cost of the apples will be $3.50.