=+Last Next-to-the-Last Purchases Invoice Purchases Invoice Quantity Unit Quantity Unit Description Purchased Cost Purchased Cost Alpha 10 30 $ 60 40 $ 59 Beta 30 25 170 15 180 Charlie 4 20 132 15 131 Echo 9 150 25 100 27 Frank 6 6 550 15 540 George 15 90 16 100 15 Killo 6 8 400 4 398 Quebec 12 500 6 500 7 Romeo 7 75 25 80 26 Sierra 3 5 250 4 260 Washburn 2 100 15 115 14 X-Ray 4 10 750 8 740 Instructions