15*5=75
79-75=4
If Luis gives each of his classmates 5 pencils each, he will have 4 leftover to give to his teacher
16*4=64
79-64=15
If Luis gives himself AND each of his classmates 4 pencils each, he will have 15 leftover to give to his teacher
So... If Luis decides to take an equal share of pencils along with his classmates, his teacher will receive more pencils.