The unit price refers to the price per individual unit. In this case, we are looking for the price per pencil because the pencil is the unit. To do this, we will divide the whole cost by the amount of pencils, so we create a fraction.
Brand A:
unit price = 2.36/18 = .131
So, Brand A sells each pencil for $.131.
Rounded to the nearest cent would be .1
or 10 cents
Brand B:
unit price = 4.09/24 = .170
Rounded to the nearest cent would be .2 or 20 cents
So, Brand B sells each pencil for $.170
Since we know the unit rates, we know that Brand A sells each pencil for less, so Brand A is a better deal.