There are 6 red balloons and 3 yellow balloons in the box, and if you take out 4 balloons at random,

Then there is at least 1 red balloon out of 4 balloons. This is a probability calculation.

Theorem: Let a and b be mutually incompatible events (ab=), then:

p（a∪b）=p（a）+p（b）

Corollary 1: Let a1 and a2 、..., an is incompatible, then: p(a1+a2+..an)= p(a1) +p(a2) +p(an)。

Take out any 4 balloons, since there are only 3 yellow balloons, then there is at least 1 red balloon out of the 4 balloons.

There were six red balloons in the box, and four balloons were taken out of the three yellow balloons, and the results were given four different results. One. The red balloon has three yellow balloons, two red balloons, and two red balloons.

Three red balloons, one yellow balloon. All four are red.

It could be all red or red and yellow, and that's all there is to it.

It's a matter of probability. For example, if you take any 4 balls, the probability of all red balloons is 5 42, and the probability of having 3 yellow balloons and 1 red balloon is 1 21.

The maximum probability is that there are both red and yellow balloons.

There are four types of balloons: 3 yellow, 1 red, 2 yellow, 2 red, 1 yellow, 3 red, and 4 red.

As a result, 1 out of 4 balloons must be red.

The result is that at least one of them is a red balloon.

There are 4 results:

red. Red 1 yellow.

Red 2 yellow. Red 3 yellow.

As a result, there are 5 balloons left, hahahaha.

There are 4 outcomes for any 4 balls.

a red ball; 1 yellow ball, 1 red ball;

yellow balls, 2 red balls;

Yellow balls, 3 red balls.

Permutation and combination of question features:

1. Abstracting several specific mathematical models from a wide variety of practical problems requires strong abstract thinking ability;

2. The constraints are sometimes vague, which requires us to accurately understand the key words in the problem (especially logical correlations and quantifiers);

3. The calculation method is simple, and there is little connection with old knowledge, but the amount of thinking required to choose a correct and reasonable calculation scheme is large;

4. Whether the calculation scheme is correct or not can often not be tested by intuitive methods, which requires us to understand the concepts and principles, and have strong analytical ability.

There are 6 red balls and 3 yellow balls in the box, and there are 4 outcomes for any 4 balls.

1. One is 4 red balls.

2. One is 3 red and one yellow.

3. One is 2 red and 2 yellow.

4. One is one red and three yellow.

Note: The above results are results that ignore the order in which they are taken.

There will be a result, one is 4 red balls, one is 3 red and one yellow, one is 2 red and 2 yellow, and one is one red and three yellow.

Summary. The 48th is a yellow balloon.

Put 1 red balloon and 3 blue balloons between every 2 yellow balloons, what color is the 48th balloon, if there are 45 balloons.

The 48th is a yellow balloon.

Put 1 red balloon and 3 blue balloons between every 2 yellow balloons, what color is the 48th balloon, if there are 45 balloons.

2+1+3 6pcs, 48 6 8, and the 8th is yellow.

Did you receive the teacher's answer Kiss received a reply to the teacher<> received. The 45th is a red balloon.

45 6 7 groups .....3 pcs.

The third is red, so the 45th is a red balloon.

Kiss Did you receive the teacher's answer Kiss Received a reply from the teacher<> The 45 balloons in the back are a few colors each.

There are 15 yellows: 7 2+1.

There are 7 1 + 1 8 red balloons.

Blue balloons: 7 3 21 pcs.

Did you receive the teacher's answer Kiss Received a reply to the teacher<> I received it, I replied, thank you, teacher.

If you have any questions you don't understand, or if you have any difficulties with your homework, you can always consult me.

There are balloons in each group: 2 + 1 + 3 = 6 balloons.

The colors are: yellow, red, blue, blue, blue, yellow.

Because: 48 6 = 8 groups.

So: the 48th is the yellow book.

Because: 45 6 = 7 groups....3 pcs.

So: the 45th is blue.

Analysis: This question is about arranging in a regular order. According to "1 red balloon and 3 blue balloons between every two yellow balloons", it can be known that there are a total of 6 balloons in each group, and the colors of these 6 balloons are yellow, red, blue, blue, blue, and yellow.

To ask what color the 48th balloon is, we can use 48 6 = 8 group, there is no remainder in the result here, which means that the 48th balloon is the same color as the last balloon in each group. Because the color of the last balloon is yellow, the color of the 48th balloon is yellow. Asking what color the 45th balloon is, we can disrupt the posture with 45 6 = 7 groups....3, the remainder is 3, which means that the color of the 45th balloon is the same as the color of the third balloon in each group, because the third balloon in each group is blue, so we say that the color of the 45th balloon is blue.

8 or 18 pcs.

According to the question bank test questions: there are 13 red balloons, the difference between yellow balloons and red balloons is 5, how many yellow balloons are there? The answer is parsed as:

8 or 18 pcs. 13+5=18 (pcs), 13-5=8 (pcs). A:

There are 18 or 8 yellow balloons.

A balloon is a sealed bag filled with air or some other gas. Balloons can be used not only as toys, but also as a means of transportation. There are many types of balloons, but now we will introduce balloons made of natural latex, which can be used as decorations, and arches made at the opening ceremony of Yuzidou.

There are 6 red balls and 3 yellow balls in the box ear sail, and there will be 4 results if you take out 4 balls at random.

1. One is 4 red balls.

2. One is 3 red and one yellow.

3. One is 2 red and 2 yellow.

4. One is one red and three yellow.

Note: The above results are results that ignore the order in which they are taken.

Take two balls out of the box, regardless of the order of the balls' colors, in the following cases:

1.Remove 2 red balls: There are 4 red balls in total, and the number of schemes to take out any 2 of them is c(4,2)=6.

2.Removal of 1 red ball and 1 white ball: There are 4 red balls and 3 white balls, and the number of programs to take out 1 red ball and 1 white ball is 4 3 = 12.

3.Take out 1 red ball and 1 yellow ball: There are 4 red balls and 5 yellow hole Mazhou balls, and the number of schemes to take out 1 red ball and 1 yellow ball is 4 5 = 20.

4.Take out 2 white balls: There are 3 white balls, and the number of solutions to take out any 2 of them is c(3,2)=3.

5.Removal of 1 white ball and 1 yellow ball: There are 3 white balls and 5 yellow balls, and the number of programs to remove 1 white ball and 1 yellow ball is 3 5 = 15.

6.Remove 2 yellow balls: There are 5 yellow balls in total, and the number of regimens to remove any 2 of them is c(5,2)=10.

Therefore, the number of schemes for removing two balls from the box is 6 + 12 + 20 + 3 + 15 + 10 = 66.

There are 6 possibilities in total: red-red, white-white, yellow-yellow, red-white, red-yellow, white-yellow. Among them, the highest probability is yellow and red and yellow.

The two balls touched are red balls, and the width of the ball is one-tenth of the size.

For example, if you find two at a time, there are the following 10 possibilities: (Yellow 1, Yellow 2), (Yellow 1, Yellow 3), (Yellow 1, Red 1), (Yellow 1, Red 2), (Yellow 2, Yellow 3), (Yellow 2, Red 1), (Yellow 2, Red 2), (Yellow 3, Red 1), (Yellow 3, Red 2), (Red 1, Red 2), and there is only one case where you can touch all red balls.

1 10 = 1 in 10.

A: There is a 1 in 10 chance that both balls touched will be reds. Hidden.

The yellow ball is 7/13 of the red ball.

For example, if you find two at a time, there are the following 10 possibilities: (Yellow 1, Yellow 2), (Yellow 1, Yellow 3), (Yellow 1, Red 1), (Jane Dust Yellow 1, Red 2), (Yellow 2, Yellow 3), (Yellow 2, Red 1), (Yellow 2, Red 2), (Yellow 3, Red 1), (Yellow 3, Red 2), (Red 1, Red 2), among which there is only one case where you touch all the red balls of the nuclear clan, 1 10 = 1/10.

A: There is a 1 in 10 chance that both balls touched will be reds.

The yellow ball is 7/13 of the red ball.

Summary. Expand on the principle of the pigeon cage, also known as the principle of drawers: if there are five pigeon cages and the pigeon keeper has 6 pigeons, then when the pigeon flies back into the cage, at least one cage contains 2 pigeons.

There are a total of 35 balloons with four different kinds of red, yellow, canopy blue, and Zheng Sui green, and a balloon should be taken out arbitrarily from it, shouting and opening and ensuring that at least 3 of them are the same color, a

Dear, the question is incomplete, can you please take a picture of the original question?

Dear, is it asking a minimum?

This is the use of the pigeon cage principle, first take 5, there must be 2 of the same, then take four, and one is the same as the first two, so 5 + 4 = 9 (pcs).

aThe minimum value is 9

Expand the introduction of the source of the pigeon cage original filial piety liquid theory, also known as the drawer principle: if there are five pigeon cages, the pigeon keeper has 6 pigeons, hail is cautious then when the pigeon flies back into the cage, at least one cage contains 2 pigeons. This simple fact is the well-known pigeon cage principle, which in our country is more commonly known as the drawer principle.