开始时:6*5/(1-5/60)=30/(1-1/12)=30/(11/12)=360/11=32又(8/11)分
做完时:(7*5-180*(60/360))/(1-5/60)=(35-30)/(1-1/12)=5/(11/12)=60/11=5又(5/11)分
(60+5又(5/11))-32又(8/11)=65又(5/11)-32又(8/11)=32又(8/11)分
做32又(8/11)分钟作业.
开始时:6*5/(1-5/60)=30/(1-1/12)=30/(11/12)=360/11=32又(8/11)分
做完时:(7*5-180*(60/360))/(1-5/60)=(35-30)/(1-1/12)=5/(11/12)=60/11=5又(5/11)分
(60+5又(5/11))-32又(8/11)=65又(5/11)-32又(8/11)=32又(8/11)分
做32又(8/11)分钟作业.