12 * 3 = 36 oameni in 12 coloane cate 3
12 * 4 = 48 oameni in 12 coloane de cate 4
12 * 5 = 60 oameni in 12 coloane a cate 5
36 + 48 + 60 = 144 oameni
daca punem cate 9 coloane vor fi 108 oameni
daca punem cate 10 coloane vor fi 120 oameni
daca punem 11 coloane vor fi 132 oameni