pencils come in packs of 20 for 2.79 if 18 8th graders and 19 7th graders need 4 pencils how much would it cost?

total students: 18+19 = 37

packs needed for 37 pencils: 37/20 or two packs

cost: 2*2.79 = 5.58

To find the total cost of the pencils needed by the 18 8th graders and 19 7th graders, we need to calculate the total number of pencils required and then multiply it by the cost per pencil.

The total number of students is 18 (8th graders) + 19 (7th graders) = 37 students.

Each student needs 4 pencils, so we multiply the number of students by the number of pencils per student: 37 (students) * 4 (pencils per student) = 148 pencils.

Now, we divide the total number of pencils by the number of pencils in a pack to determine the number of packs required: 148 (total pencils) / 20 (pencils per pack) = 7.4 packs.

Since we can't have a fraction of a pack, we need to round up to the next whole number. Therefore, we need a minimum of 8 packs of pencils.

The cost of each pack is $2.79, so we multiply the total number of packs by the cost per pack to find the total cost: 8 (packs) * $2.79 (cost per pack) = $22.32.

Therefore, it would cost $22.32 for the 18 8th graders and 19 7th graders to purchase 4 pencils each.