Ask for a few questions from Fun Math 366

It's a dead look, oh look at me, look at the memory card first.

Summary. Interesting math problems (6 questions) are explained in detail and easy to understand! 1.

For a project, A does it alone in 20 days, and B does it alone in 15 days. The project was first completed by A for a number of days, and then completed by B alone, taking 18 days from the start to the completion. How many days did A and B each do?

2.A highway is repaired by two road construction teams, A and B, and it takes 12 days to complete. Now after 3 days of repair by team A, and 1 day by team B, a total of 3 20

If this road is completely repaired by Team A alone, how many days will it take to complete it? 3.A project A and B teams cooperate to complete in 9 days, teams B and C cooperate in 12 days, and teams A and C work together in 18 days.

How many days does it take to complete the process if the team is working together? 4.The cistern has an inlet pipe and an outlet pipe.

The single water inlet pipe fills the whole pool in 5 hours, and the single open drainage drains 3 hours to release a pool of water. Now there is half a pool of water in the pool, if you press the inlet water, drain, inlet water, drain. In this order, each one hour is turned on for one hour, and after how many hours the pool is just empty?

5: A project, the master does 8 hours a day, 15 days to complete.

Interesting math problems (6 questions) are explained in detail and easy to understand!

Interesting math problems (6 questions) are explained in detail and easy to understand! 1.For a project, A does it alone in 20 days, and B does it alone in 15 days.

The project was first completed by A for a number of days, and then completed by B alone, taking 18 days from the start to the completion. How many days did A and B each do? 2.

A highway is repaired by two road construction teams, A and B, and it takes 12 days to complete. Now after 3 days of repair by team A, and 1 day by team B, a total of 3 20If this road is completely repaired by Team A alone, how many days will it take to complete it?

3.A project A and B teams cooperate to complete in 9 days, teams B and C cooperate in 12 days, and teams A and C work together in 18 days. How many days does it take to complete the process if the team is working together?

4.The cistern has an inlet pipe and an outlet pipe. The single water inlet pipe is filled with the whole pool in 5 hours, and the single open drainage is completed in 3 hours.

Now there is half a pool of water in the pool, if you press the inlet water, drain, inlet water, drain. In this order, each of them is open for one hour in turn, how many hours after the rise of the pond is just drained? 5：

For a project, the master does it for 8 hours a day and completes it in 15 days.

6.It takes 14 hours for A to complete a manuscript and 20 hours for B to complete it alone. Now A will fight for 1 hour, and then B will play for 1 hour, and then A will take over from B for 1 hour.

How many hours does it take to complete this manuscript?

Interesting mathematics class emphasizes "movement", "movement" is the student's multiple senses in the class, and all kinds of teaching should be fully mobilized, especially hands-on operation or creating a regretful situation for students to participate in (or simulate the first bridge) practice, so that students can use and learn in learning.

1111 Fun + 111 Taste + 11 Number + Learning = 6761 If Fun = 5, then 6761-5555 = 1205, not true.

Therefore, fun = 6

Taste = 0 number = 8 learning = 7

It's really interesting, but the crux of the matter lies in the algorithm of the total room rate.

250 paid.

300 20 Waiter Private Collection.

50 return 30 real return.

Now the total room fee of 300 in the question is unreasonable to use the 90 paid per person plus the 20 that the waiter has kept privately.

Because there is no direct relationship between the two.

The difference between the total room rate and the actual room price is 50, and this 50 is called the difference.

The three of them each paid 90, a total of 270, of which 20 went into the waiter's pocket, and the remaining 250 is the actual house price, plus 50 The difference is the total house price.

And using 270 plus 20 as the total house price is confusion.

At 0:00:00, the three hands coincided, and the catch up on the clock face began.

The hour hand travels 30 degrees per hour.

The minute hand travels 360 degrees per hour.

The second hand travels 21,600 degrees per hour.

Let the three hands of x hours, y, minutes and z seconds after 0 o'clock (and before 12 o'clock) coincide, that is, there is:

30（x + y/60 + z/3600) = 360(y/60 + z/3600) = 21600z/3600

That is: 360x + 60y = 720y + 11z = 719z (0 y, z 60, 0 x 12).

This system of equations has and only a solution.

x = y = z = 0

That is to say, in a day, only three needles all point to 0 o'clock, and they coincide exactly, and the times are:

0:00:00, 12(0):00:00, 24(0):00:00.

In 24 hours, the hour, minute and second hands overlap three times.

All three overlap three times, 0 o'clock, 12 o'clock, 24 o'clock!

3 times, 0:00:00, 12:00:00, 24:00:00.