It was $6.00 per pound. So 2 pounds would be $12. But there is still that .6 of a pound left. If we know 1 pound costs $6, then we know 1/10th of a pound will cost $0.60. So 6 x .60 = 3.60. Add 12 and 3.60, and you get 15.60 for 2.6 pounds of granola at the old price.