Sebastian purchased 1.4 pounds of coffee for $7.65 per pound.
a. how much will sebastian pay for the 1.4 pounds of coffee?

$10.71

Step-by-step explanation:

Sebastian is going to pay ten dollars and seventy one cents ($10.71‬) for the one point four pounds of coffee.

For every pound of coffee it is seven dollars and sixty five cents ($7.65).

Instead of adding seven point sixty five (the amount per pound) one point four times (pounds of coffee), it is easier to multiply. So, let's multiply one point four and the amount per pound ($7.65).

(I am taking away the dollar sign for now! The dollar sign we can ignore for now!)

7.65 x 1.4 = 10.71

$10.71