( 1 12 + 1 15 ×2)+( 1 12 ×2+ 1 15 )=( 1 12 + 2 15 )+( 1 6 + 1 15 )= 13 60 + 7 30 = 9 20 ,12+1+(1- 9 20 ×2- 1 12 )÷ 1 15 =12+1+ 1 60 ÷ 1 15 =13 1 4 (小时),答:打印这部稿件共要13 1 4 小时,故答案为:13 1 4 .