Practical questions in the first half of the first semester of junior high school, and application q

2.Let the speed of the red team be 9V and the speed of the Yellow team be 10V, and the remaining time of the red team = (3000-1800) 9V*

Yellow team's remaining time = (3000-2000) 10v = 1000 10v vertical rush arrives at the same time with no stupid annihilation.

3.The yellow team arrives first, the distance between the two teams = the time difference * the speed of the red team = 120km

Let's say A does x per day and B does y per day.

4x+8*(x+y)=840

4y+9*(x+y)=840

The solution yields y=30 and x=50

A makes 50 per day, and B makes 30 per day.

Let A do x per day and B do y per day The system of equations is as follows.

4x+8x+8y=840

4y+9y+9x=840

If you're in the first year of junior high school, you should be able to figure it out.

If all 45 tickets are Class A, you will need 45* yuan.

It's more diverse than it actually is.

For every less type A ticket, there will be one more type B ticket, and there will be less.

So there are 5 tickets for type B.

So there are 45-25=20 tickets for type A.

A: A and B bought 20 and 25 tickets respectively.

Hope it helps!

B is equal to 25 and A is equal to 20.

Columnar calculation: A + B =

A + B = 45

I don't know if you know what you know.

Let A x and B y then according to the meaning of the topic can be listed x+y=45, x=20, y=25

So 20 sheets for A and 25 sheets for B.

Set: A x sheets, Y sheets have been planted.

x+y=45

Solution: x=20

y=25 Answer: 20 sheets of seed A, 25 sheets of seed have been planted.

Set up type A movie tickets to buy x tickets, and type B to buy 45-x tickets.

x=2045-20=25 (sheets).

Answer: Type A bought 20 tickets, and Type B bought 25.

In the first year of junior high school, set an unknown number, A x sheet, B (45-x) sheet, solve x = 20, so A bought 20 sheets, B bought 25 sheets.

Since it is a question in the first year of junior high school, you can use equations to solve it:

If there are x million people who use air transportation every year, then there are (500-x) people who use sea transportation.

According to the title, the following formula can be obtained:

4 x + 22 x (500-x) = 29 million.

The number may be very large, I wonder if it should be 2900 hours in the LZ problem? , but according to the above question, you can also solve x=1610500, I wonder if there are errors in the numbers and units in the question?

The above idea is correct, but the solution is wrong.

4x+22*500-22x=2900

Solution x=450

4.5 million people by sea and 500,000 people by air.