If a jumbo pie has 12 slices and you need a total of 40 slices, you can calculate how many jumbo pies you should buy by dividing the total number of slices needed by the number of slices in each jumbo pie:
Number of Jumbo Pies = Total Slices Needed / Slices in Each Jumbo Pie
Number of Jumbo Pies = 40 slices / 12 slices per jumbo pie
Number of Jumbo Pies ≈ 3.33 pies
Since you can't buy a fraction of a jumbo pie, you would need to buy at least 4 jumbo pies to get a total of 48 slices (4 pies * 12 slices per pie), which exceeds the 40 slices you need.