Then notify 1 person at 1 minute. At this time, * * * 1 students have been informed, and two people (teachers and informed students) know the situation, and the call duration is 1 minute.
Two people will be notified in the second minute. At this time, three students will be informed, and four people will know the situation and talk for two minutes.
In the third minute, four people were informed. At this time, * * * informed seven students, and eight people knew the situation. The call lasted four minutes.
Eight people were notified in the fourth minute. At this time, * * * 15 students were informed, and 16 people understood the situation and talked for 8 minutes.
At the 5th minute, 16 people were notified. At this time, * * * 3 1 students were informed, and 32 people understood the situation. Call duration 16 minutes.
With the above list, we can find out the rules. The number of people notified in the first n minutes is twice that in the first n- 1 minute, which is more than that in 1. In essence, everyone who notified before informed another person within 1 minute, plus the teacher informed 1 person.
2 n- 1 person was notified n minutes before the conclusion (2 n is n times 2).
Call 2 (n- 1) in the nth minute * *, and the call times are added. A * * * call1+2+4+8+16 = 31min, and the call charge is 6.4 yuan.
In fact, how many times do you have to call to inform the number of people? To call 3 1 person, you need to call 3 1 time, that is, the total talk time is 3 1 minute. Using different modes, the time required to complete typing is different.
Extended data:
There are three solutions to the telephone problem:
1, the teacher's notice;
2. Group notification;
Each student will inform other students immediately after receiving the notice.
Obviously, using the third scheme, every student who receives the notice can inform other students, which is more efficient.
Through the analysis, we can find that the number of students who receive the notice every minute doubles, and the number of freshmen who receive the notice every minute is the sum of the number of students and teachers who have received the notice before. Through analogical reasoning, formulas can be summarized.
When the third scheme is applied in life, it is necessary to design a program in advance to explain who will inform whom to avoid duplication or omission.