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Mathematical problems. It's simple.
The first question, this can be counted as a series of questions.

Minute 1: two people have been conveyed = 1 (Ministry)+1 (No.65438 +0)

Minute 2: 4 people have been communicated = 1 (Ministry)+1 (No.1) +2 (Ministry andNo. 1 notified 1 person respectively).

Minute: 8 people have been communicated = 1 (Ministry)+1 (decree) +2 (Ministry and decree number. 1 Notify separately 1 person) +4 (four known people notify one person each).

..... the nth minute: It has been conveyed that a person =2A(n- 1), that is, {An} is a geometric series with a common ratio of 2.

Therefore, at most 8 people can be notified in 4 minutes, and the topic needs 7 people, so it takes at least 4 minutes to convey all the messengers.

The second question is that my brother got X and my brother got Y.

According to the meaning of the question, Y- 1=X+ 1.

Y+2=3X gives X=2 Y=4, so X+Y=6 There are 6 pears in the plate.

The third question shows that a cat can catch a mouse in one minute, and 100 mice need 1 cat to catch it in 100 minutes.

I'm so tired from playing ~ ~ ~

Question 4: Because three people have a bad relationship, they will not vote for the same person, so no matter who they are, they will lose these two votes. So 40-2=38 38/2= 19, as long as you get 19 votes, you can ensure that you are elected as a satrap.

There are three ways to reach the fifth question, namely 3+3+3+ 1 1, 3+3+7+7, 5+5+5, so the answer is 4 times.

The sixth problem can be regarded as that Liu Bei has no change, that is, as a result, he took 50 taels of fake goods in his hand and asked for 20 taels.

Without a pair of shoes of 30 taels, I lost 20+30=50.

The seventh question, Cao Chong is X years old and Cao Zhi is Y years old.

According to the meaning of the question X+5=Y 2X=Y, it is concluded that X=5 Y= 10, so Cao Chong is 5 years old (all other conditions are deceptive).

The eighth question 1 used five people, * * * saved five people, and it took nine minutes.

I picked up 5 people for the second time, and 5+5 people were * *, which took 9+9= 18 minutes.

The third time, I picked up 5 people and * * * saved 5+5 people. Because there are still two minutes to pick up the last batch of people, the last batch of people can still be saved, so the rescue boat can rescue 15 soldiers at most.