One , Weighing rice

Problem description

* existing ： rice 9 Kg ,50 One gram weight ,200 One gram weight
* ask ： How to weigh only on a balance 3 Second, weigh out 2 Kilogram meter ?

Two , Time calculation of burning rope

Problem description

* Burn an uneven rope , All in all 1 hour . Now there are several ropes of the same material , ask ： How to use the method of burning rope 1 Time 15 What about the points ?

Three , Gold bars for workers

Problem description

*
If you let workers work for you 7 day , The reward is a gold bar . The gold bar was divided into two parts 7 paragraph , You have to give them a gold bar at the end of each day . If you're only allowed to break the bar twice , How do you pay your workers ?

Four , Contaminated pills

Problem description

* You have 4 A jar of pills , Each pill has a certain quality , Contaminated pills are the quality of unpolluted pills +1. Weighing only 1 second , How to judge which jar of medicine is contaminated ?

Five , Weighing cans

Problem description

*
The delivery man delivered it to a food company 10 Boxes of canned pineapples . What is the quality of each can 800 gram , In each case 20 individual . But this 10 There is one box mixed with defective products due to machine problems , Every can is 50 The component of gram . So how to weigh out that box of unqualified products at one time ?

Six , Yes 20 How many bottles of soda can you drink for yuan

Problem description

* 1 Yuan for a bottle of soda , After drinking, change two empty bottles for one soda . ask ： You have 20 Yuan , How many bottles of soda can you drink at most

Seven , Disappeared 1 Yuan

Eight , Sub items

Problem description

* existing ：7 One gram weight ,2 One gram weight , A balance
* ask ： How to use these items only 3 The second general 140 G of salt 50,90 One for each ?

* method 1：

* method 2：

* But the method 2 Comparison method 1 good , Because of the method 2 pass the civil examinations 3 It is necessary to put the 1 Find a place to store the weighed salt
Nine , Weigh out 4 Liters of water

Problem description

* If you have infinite water , One 3 Up and one 5 A liter bucket , How do you weigh it accurately 4 Liters of water ?

Ten , Sequencing problem

Problem description

* Yes 4 Balls of the same size , They are methyl ethyl propionate ：
* A and B are on the side of the scale , C and D are on the other side , The balance is basically in balance
* Exchange of ethylene and propylene , B and D are heavier on the other side
* One side is Jiading , On the other side is B , B is heavy

eleven , How to weigh it 3 The ball was found every time

Problem description

* Yes 12 Balls , A balance , Now it is known that only one weight is different from the others , ask ： How to weigh it 3 I found the ball every time ?

* The difficulty of this problem is that we don't know whether the ball we are looking for is heavier or lighter than others
* The method is as follows ：
* take 12 The balls are numbered as 1~12
* First weighing ： take 1~4 Put it on the left side of the scale , take 5~8 Put it on the right side of the balance ,9~12 Hold still
* After the first weighing , Divided into the following 3 Situation

twelve ,3 The age of a daughter

Problem description

*
A manager has 3 A daughter ,3 The age of the daughters adds up to 13,3 The age of a daughter multiplied by the age of the manager . One of the subordinates already knows the age of the manager , But the manager is still uncertain 3 The age of a daughter . At this time, the manager said that only one daughter's hair was black , Then the subordinate knows the manager 3 The age of a daughter
* Excuse me? ：3 What are the ages of the daughters ? Why?

thirteen , Who will finish first 40 Down the mouse

Problem description

* Ralph participated in the mouse click competition , Willie and Paul . Ralph 10 Seconds can hit 10 Down the mouse ; Willy 20 Seconds can hit 20 Down the mouse ; Paul 5 Seconds can hit 5 Down the mouse
* The time spent by each of the above is calculated as follows ： Start with the first strike , To the end of the last strike
* ask ： Can they draw ? If not , Who will finish first 40 Down the mouse

fourteen , be able to develop one 's ability to the full

Problem description

* Doruf , Philip , Robert 3 Young people , One became a singer , One was admitted to university , One joined the US Marine Corps
* Know now ：
* A. Robert is younger than a soldier
* B. College students are younger than Philip
* C. Doruf's age is different from that of college students

fifteen , Bridge crossing

sixteen , An untrustworthy word

seventeen , Pirates share gems

eighteen , Insect

Problem description

* （1） Where do you always find happiness ?
* （2） When a man comes into his garden , Always put what in first ?
* （3） What gets dirtier after washing ?
* （4） What can carry a hundred bales of hay but not a grain of sand ?
* （5） What is more popular when it is broken ?
* （6） What do you never eat at breakfast ?
* （7） What about things that a magnifying glass can't magnify ?
* （8） What increases by half when you stand on your head ?