高考问答疯狂小杨哥:英语数学题
来源：百度文库 编辑：高考问答 时间：2024/04/30 11:11:51
The principal of a new elementary school sounded the alarm for fire training. It took a very long time to empty the building. It was evident that the schoolchildren were at risk. The school has three exterior doors. The main door is served by a wide corridor, the side door by a narrower corridor, and the rear door by a dog-legged corridor.
By experimenting with the classrooms adjacent to each of these doors, it was determined that:
About 1.5 minutes elapse between the announcement of an emergency and the first departure through each door.
Students and staff can file through the doors at these rates approximately 55 per minute through the main door, 30 per minute through the side door, and 25 per minute through the rear door.
About 450 persons are inside the building.
Calculate for the problem the minimum time until the building empties
a.4.1
b.1.5
c.5.3
d.5.6
e.8.18
By experimenting with the classrooms adjacent to each of these doors, it was determined that:
About 1.5 minutes elapse between the announcement of an emergency and the first departure through each door.
Students and staff can file through the doors at these rates approximately 55 per minute through the main door, 30 per minute through the side door, and 25 per minute through the rear door.
About 450 persons are inside the building.
Calculate for the problem the minimum time until the building empties
a.4.1
b.1.5
c.5.3
d.5.6
e.8.18
D，有题意可知道，发生险情后1.5分钟开始各自疏散，大门每分钟过55人，中门每分钟过30人，小门每分钟过25人，总共每分钟过55+30+25=110人，疏散时间为450/110=4.1分钟，再加上发现险情的时间1.5分钟，至少为5.6分钟
The answer might be d:5.6.