You have to pay $9.60 for 24 ounces of the sandwich spread.
Given:
Unit cost of sandwich spread = $6.40 per pound
Weight of sandwich spread = 24 ounces
We need to convert the ounces into pound before we can compute the cost of the sandwich spread.
1 pound is equivalent to 16 ounces.
24 ounces x 1 pound/16 ounces = 24 pound/16 = 1.5 pounds
total cost of 24 ounces sandwich spread
1.5 pounds x $6.40 per pound = $9.60