If 3 pencils cost $2.40, how much does one pencil cost?

To determine the cost of one pencil when 3 pencils cost $2.40, you need to divide the total cost by the number of pencils.

Calculating this, you would take $2.40 and divide it by 3:

[

\text{Cost of one pencil} = \frac{2.40}{3} = 0.80

]

This means that each pencil costs $0.80, which matches the correct answer. This method—dividing the total amount by the quantity—accurately reflects how to find the unit price of items in bulk, making it a fundamental concept in basic arithmetic and budgeting.