Find the answer to the following math problem, to explain!

Answer: First, let t1 be the time from A to B, and t2 to be the time from B to A.

By the formula time = distance velocity, so t1 = 480 80 = 6 hours; t2 = 480 60 = 8 hours.

And by the formula average velocity = total distance and total time, so the average velocity is 480*2 (6+8)=

Finally, keep the integer at 69km h

The average speed is equal to the distance traveled divided by the time!! The problem provides that A and B are 480km apart, then the distance is 480 times 2, which is equal to 960, assuming that the time to go is x and the time to return is y, then there are 80x=60y=480, and the average velocity is 960 divided by (x+y), and the answer is about.

Average speed = total distance and total time.

480 2 = 960 km Total distance round trip.

480 80 = 6 hours Departure time.

480 60 = 8 hours on return.

960 (6+8) is approximately equal to 69 km.

Solution: 480 80 = 6 (hours), 480 60 = 8 (hours), 480 2) (6 + 8) and so on about 69 (kilometers per hour), A: The average speed of this person is about 69 kilometers per hour

The time from A to B t1 = 480 80 = 6 hours.

The time from B to A t2 = 480 60 = 8 hours.

Total time t=t1+t2=14 hours.

Therefore, the average round-trip speed is 480*2 14=hours.

is to find the average velocity, adding up the velocities of the two: 60 plus 80 equals 140 (kilometers per hour). Divide the sum by 2 to get 70 (kilometers in kilometers). A: The average speed of this person is 70 kilometers per hour.

It took 6 hours to go and 8 hours to come back. A total of 14 hours, a total of 480 * 2 = 960 kilometers of walking. Therefore, the average speed is 960 14 = 69 km/h (the result is rounded).

The time taken from A to B t1 = 480 80 = 6, and the time taken from B to A is t2 = 480 60 = 8

The average round-trip speed v=(480*2) (6+8).

Walking distance 2*480=960

Time taken 480 80 + 480 60 = 14

The average speed of 960 14 = is approximately equal to 69

Average velocity refers to the ratio of the displacement of the motion of an object to the time taken in a certain period of time, it is a vector quantity, and it is directional. So? The average speed of the person's round trip is equal to zero.

Solution: 480 80 = 6 (h).

480÷60=8（h）

69 (km/h)

A: The average speed of this person round trip is about 69km per hour.

Horizontal is a row and vertical is a column, the 3rd row of the 6th column is expressed as the 3rd row and the 6th column is clear, and the 2nd row 6=30

One row is 12 and the same row and column, so it is 12 rows and 12 columns.

A total of 12 12 = 144

set, there are x columns.

2x+6=30

Solution: x=12 (column).

So: Venus Elementary School has a total of athletes = 12 12 = 144 (people).

The square of (sina + cosa) = the square of sina + the square of cosa + 2 * sina * cosa = the square of m So we get the square of 1+2*sina*cosa=m and because sina*cosa=n gives the square of 1+2n=m.

m^2－1＝2n.Square the first formula; Finishing is available.

Solution: You can set u=|1-x|,（x∈r).Knowable, u 0Therefore 0 (1 2) u 1===>m＜m+(1/2)^u≤1+m.It is easy to know, when -1 m 0 is enough.

Let's go to the absolute value first.

y=(1/2)^(x-1)+m (x>1)y=2^(x-1)+m (x<1)

The range of y is (m,m+1].

So -1

1.The first of the two equations is greater than zero, and the second x=1 function is less than zero.

2 is the same principle as above, first Dahl is greater than zero, and then ensure that the value of the x=2 function is less than zero.

1. The number that can be taken is 2-98, a total of 97.

2. The number that can be taken is 3-97, a total of 95.

3. The number that can be taken is 4-96, a total of 93.

49, the number that can be taken is 50, a total of 1.

97+95+93+91+..3+1=（97+3）+（95+5）+（93+7）+.51 + 49) Ant Void + 1 = 48 2 * 100 + 1 = 2401 (Late Celery).

Good luck with your learning and progress. Hope.

1.x+6=-3(x+2) The solution yields x=-32If the rest is to be completed in x hours, there is.

1-4*(1 20)=(1 20+1 12)x solution x=6 hours.

3.It takes x days for two people to work together.

1/4+1/6)x=1

Solution x = days.

If two people work together for x days, then.

1-1/6=(1/4+1/6)x

If the solution is x=2, then the master's remuneration is 450*2 4=225 yuan, and the apprentice's remuneration is 450-225=225 yuan.

If the two work together for 2 days, and then the master leaves due to something, and the rest of the work is completed by the apprentice alone, how many days do they need to work?

Solution: If you still need to work for x days to set up an apprentice, there is.

1-(1/4+1/6)*2=1/6x

Solution x=1

2.First, calculate the least common multiple of B and A, 60Then divide 60 by 20 to get 3 is that A completes 3 copies per hour, 60 by 12 to get 5 is B completes 5 copies per hour, then 3 times 4 to get 12 is what A does, 60 minus 12 to get 48 is the rest, and 48 divided by 3 and 5 is the sum of 6 hours.

A: The rest will take 6 hours to complete.

The rest of the questions are similar to this, think for yourself.

Solution: If A bonsai x is needed, then B bonsai is 2 3x.

So there is x+2 3x=2000

5/3x=2000

x=1200

So there are 1200 A bonsai and 800 B bonsai.

Therefore, the money to buy bonsai is 15x1200 + 800x20 = 34000 yuan.

Method 2: The number of A is: 2000 (1+2 3)=1200, and the number of B is: 1200*2 3=800.

The total cost is: 15 * 1200 + 20 * 800 = 18000 + 16000 = 34000 yuan.

Solution: If A bonsai x is needed, then B bonsai is 2 3x.

So there is x+2 3x=2000

5/3x=2000

x=1200

So there are 1200 A bonsai and 800 B bonsai.

Therefore, the money to buy bonsai is 15x1200 + 800x20 = 34000 yuan.

I hope mine can help you.

Hope o ( o thank you.

Good luck with your learning and progress.

Let a bonsai x, then b bonsai 2000-x2 3 times x = 2000-x solution x=1200 then a bonsai 1200, b bonsai, 800

1200x15+800x20=34000 yuan.

What grade are you in such a simple question 2000 (3+2)=400 pots A 400*3=1200 pots b 400*2=800 pots Multiply the unit price OK with the ratio OK

Let the quantity of a and b be x,y, then there is, x+y=2000, y=2 3x, and the solution is x=1200, y=800, so it takes 15x+20y yuan, so it is equal to 34000 yuan.