There s a question, and the answer is that you don t know why

It takes half (the distance) to find it.

Let the total time be t, the total distance: 80t 2 + 70t 2 = 150t 2 = 75t = 6000;

t=6000/75=2000/25=80min;

Half (time) of the distance traveled: 80*t 2=3200>3000;

3000-200)/70=2800/70=40min;

Half (distance) time: 40+;

3000 70 = close;

Because the second half only covered 200 meters in 80m min, it is about the same.

Let the total time be t.

The distance traveled in the first half of the time: 1 2 t 80 = 40t The distance traveled in the second half of the time: 1 2 t 70 = 35t The total distance is 6000 meters, that is, 40t + 35t = 6000 to get t = 80 Your way of thinking is wrong, this question is half the time, you should use the time multiplied by the distance equal to the total distance to find, you divide 3000 by 70 is the time taken to walk half the distance, and the distance taken in half the time is not the same.

6 km = 6000 m.

Solution: Set the first half of the time with t minutes.

80t+70t=6000

t=40 (minutes).

Half of 6000 meters = 6000 2 = 3000 (meters);

Time taken for the first half of the journey = 3000 80 = minutes);

So: it takes him the last half of the journey = 40 minutes).

I don't understand the meaning of the question, this question divides the total time required into two, not the distance is divided into two, and the distance traveled in the two periods of time is not the same. Therefore it should be:

Solution: Set the first half of the time with t minutes.

80t+70t=6000

t=40 (minutes).

40*2=80 In other words, it took him a total of 80 minutes to walk this route, which means that he walked 3,200 meters at a speed of 80 meters. Then the composition of the latter part of the distance is 200 meters with a speed of 80 meters, and 2800 meters with a speed of 70 meters, then, it is 200 80 + 2800 70 = minutes.

A day and night is 24 hours, and the time of day is 5 7 of the time of night, then the time of day is equal to 10 hours, and the time of night is equal to 14 hours.

The time of the day is counted as 5 parts, and the time of the night is counted as 7 parts, and the time of each minute is equal to 24 (5 7) 2 hours, so the time of the day is equal to 5 2 10 hours, and the time between the rolling yards is equal to 7 2 14 hours.

Isn't it true that there is this day and night 5 7 you know? Search the dust 24 hours a day! It can be set that the source calendar night is x hours, then the day is 5x 7 hours hail missed search, day plus night is equal to 24 hours, that is, x+5 x 7=24, that is, 12x 7=24, that is, it is equal to 14 hours, so the night is, 14 hours, and the day is 24-14=10 hours.

This withered Wu Hong liquid Dao question should not or should be:

Day + Night = 24 hours.

White orange split day night = 5 7, group silver.

Round or closed, day = 10 hours.

Dark night = 14 hours.

Analysis: When the black ball is 1, the white ball is 1-1=0;

When the black ball is 2, the white ball is 2-1=1;

When the black ball is 3, the white ball is 3-1+3-2=3;Eliminate the wilderness.

When the source black is 4, the white ball is 4-1+4-2+4-3=6, and when black is n, the white ball is n-1+n-2+n-3+....Nabi shouts =(1+n-1) (n-1) 2=n(n-1) 2

x=(1,-2,1)'

ax=a1-2a2+a3=0x

0 is the eigenvalue, and the corresponding eigenvector is x

3 x 9 = 27 yuan + 2 yuan from the waiter = 29 yuan".

There is a problem, 10-1=9 means that each person spent 9 yuan, and 3x9=27 is a total of 27 yuan, and you can't add 2 yuan to the waiter, because 27 yuan already includes the 2 yuan that the waiter guesses.

You can subtract the pickpocket's 2 yuan = 25 is the boss received 25 + 2 = 27 spent + 3 returned = 30 is just right.

The boss now has 30-5 = 25 yuan, and now each person pays 10-1 = 9 yuan, which is 9x3 = 27 yuan, and the service Li Shucong takes 2 yuan.

No, Sakura is making up 30 but making up 25, because the boss is now taking a total of 25 yuan instead of 30 yuan.

At the beginning of the first nuclear calendar, each of them paid 10 yuan, a total of 30 yuan. Later, each person got 1 yuan, so they only paid 9 yuan per person, a total of 27 yuan. The boss got 25 yuan, and the waiter got 2 yuan, for a total of 27 yuan.

Change to proposition p: If it's a question, then you'll do it. There is proposition a:

That's a question. B: You will do so p = a ->b, proposition a says p is a problem, so you can know that proposition a is correct and p.

So the assumption is that when proposition p is false, a is true and b is false, contrary to what was obtained before. So the assumption is not true that when p is true, a is also true and b is also true, which is logical, so p proposition is true.

You can see clearly whether the inequality given by the answer is the same as yours, and you write it wrong (to be squared), use the inequality given by the answer, and you will find that it is actually possible.

Because the answer you made is problematic, the way to understand the question form is not right, right?

I don't think you should ask me because I'm not good at math, you can go and ask your teacher and he should be able to teach you.