(Originais Teachy 2024) - Question Medium of Mathematics

In a construction project, the engineer needs to determine the amount of paint needed to paint a large wall. He measured the area to be painted and obtained the value of 397.25 square meters. However, when consulting the paint manufacturer's catalog, he realized that paint cans are sold in pre-established volumes: 1 liter, 2.5 liters, and 5 liters. To optimize the cost of the project, the engineer wants to buy the smallest amount of cans possible, without failing to cover the entire wall. Considering that each paint can covers exactly the amount indicated on the label and that the paint yield is the same on any surface, determine the smallest number of 2.5-liter paint cans the engineer should buy and justify rounding to the nearest unit. Also, explain why there can be no waste when rounding the number of cans up or down.