The remaining weight of the empty bottle is 0.5 because each third of the bottle weighs 2.5 pounds and of the remaining juice and the bottle was 3 pounds 2.5 subtracted from 3 is 0.5
First you add up all the items and the coupon then you will get $24.51. then subtract $50.00 take away $24.51 then you will get $25.49. So when she left the store she had $25.49