One night in 30 yuan.

Three people each paid 10 to make up 30 yuan and gave it to the boss.

Later, the boss said that it was enough to give 25 yuan a discount today.

Take out 5 yuan and ask the waiter to return it to them.

The waiter secretly hid 2 yuan,

Then,

Divide the remaining 3 yuan money among three people,

Everyone gets 1 yuan.

In this way,

Everyone handed in 10 yuan.

Now it's back to 1 yuan,

Namely 10- 1=9,

Everyone only spent 9 yuan's money,

Three people each, 9 yuan,

3×9 = 27 yuan+2 yuan hidden by the waiter =29 yuan,

Where's the other dollar?

(2) There is a well 7 meters deep.

A snail climbed up from the bottom of the well.

Climb 3 meters during the day and drop 2 meters at night.

How many days does it take for a snail to climb out of the well?

(3) How many tables are there in a room?

If there are three people at a table, there are two more.

If there are five people at a table, there are four more.

If there are seven people at a table, there are six more.

If there are nine people at a table, there will be eight more.

If 1 1 one table for each person, that would be just right.

How many people are there in this room?

(4) Salt water with salt content of15% 1800g was prepared with two kinds of salt water with salt content of 20% and 5%. So how many grams do you need for each of the two brines?

(5) No.3 Workshop * * * produced a batch of parts. After the first workshop produced one part, the second workshop produced the remaining 20%, and the third workshop produced 800 parts, just finishing the task. How many parts are produced in the second and third workshops?

(6) The garment factory originally made a set of 3.2m garment cloth. After improving the cutting method, each set of garment cloth was 2.8m.. How many sets of cloth can you make now?

(7) Xiaohua reads 24 pages of books every day, and finishes the book Red Rock in 12 days. Xiaoming reads 36 pages a day. How many days can he finish Hongyan?

It takes an hour to throw a rope. How can we burn this rope in half an hour? (A: Burn both ends together)

(9) Suppose the clock arrives at 12. Please note that the hour hand and minute hand overlap. Day, hour hand and minute.

How many times do the stitches overlap? (0 times)

(10) If you have unlimited water, a 3-quart bucket and a 5-quart bucket, how can you accurately weigh it out?

Four quarts of dehydration? (

More complicated:

First, fill a 3-quart bucket and pour in 5 quarts. Hereinafter referred to as 3->5)

Mark b 1 in the 5-quart barrel.

B, continue to fill 5 blanks with 3, and pour 5 pieces of water into 3 until b 1 is marked b2 in 3.

C, continue to fill 3 vacancies with 5, and pour 3 waters into 5 until b2.

D, empty 3. Pour the water from 5 into 3, labeled b3.

E, fill 5 empty 3, pour 5 water into 3 until 3 water reaches b3.

It's over. Now the water in 5 is standard 4 quarts dehydrated.