Grade 6 math problems come to the master 6 questions, a 5 points!

1. Let the speed of one car be x m s, and the speed of the other car will be y m s (x>y) 80 (x-y) = 400

16(x+y)=400

Solving the system of equations yields x=15 m s, y = 10 m s.

A: The speed of the two cars is 15 m s and 10 m s respectively.

2. Design: The last two people cooperate, and then it takes x hours to complete.

1 15 + 3 12 + x (1 15 + 1 12) = 1 to solve the equation to obtain: x = 41 9

A: In the end, the two worked together, and it took another 41 to 9 hours to complete.

3: If there are six fewer workers than the original plan, the task will be completed by 4 days longer than the original plan, and if there are 6 more employees than the original plan, then the task will be completed 3 days earlier than the original plan, Q?

3. Design: The original plan was to use x people, and the original plan was to be completed in y days.

x-6)(y+4)=xy

x+6)(y-3)=xy

Solve the system of equations, x=42, y=24

A: The original plan was to use 42 people, and the original plan was to complete it in 24 days.

4. Set: the price of the commodity is X yuan.

Solve the equation to obtain: x=1955

Answer: The price of the product is 1955 yuan.

5. Set: Block A takes x g, block B takes (500-x) g80%x+60%(500-x)=74%*500 to solve the equation to obtain: x = 350, 500-350 = 150 Answer: 350g for block A and 150g for block B.

6. Suppose: take a kind of alcohol solution x kg, take a kind of B alcohol solution (14-x) kg, the ratio of alcohol to water in a bucket is 2:3, and the concentration of the solution is 40%; The ratio of alcohol to water in barrel B is 3:1, and the concentration of the solution is 75%;

According to the meaning of the topic, 40%x+(14-x)75%=50%*14 solves the equation to obtain: x=10, 14-x=4

Answer: Take 10kg of alcohol solution A and 4kg of alcohol solution B.

1。The speed of the express train is 680 (5+3)=85

Then the distance of the express train at the time of meeting is 85*5=425

If the speed of the slow train is x, then there is 5x+425=(5+3)x (1-1 4) (the distance is equal).

The solution is x=75

The distance between AB is 75*5+425=800 meters.

2。The circumference of the rectangle is twice the radius plus the circumference of the circle, i.e. (2r + radius r = cm

So the area of the circle is (square centimeters).

First set the total length of x kilometers.

8[（x÷5）-（680÷8）]=85

Once solved, it's the answer you want. The process you write yourself. Bonus points.

1. Let A and B be separated by a, then the speed of the slow train is: 3a 4 8 = 3a 32, a-3a 32 * 5 = 17a 32, this is the distance of the express train when they meet, through this the speed of the fast train can be calculated as: 17a 32 5 = 17a 160, and then through the distance of the express train, it is obtained:

17a 160*8=680, from which it is calculated that a=800 km.

First question: AB and the two places are 800 kilometers apart.

The speed of the fast train is 680 (3+5)=85 km/s, and the speed of the slow train is skm/h

5*85=3*s+ab/4

ab=8*s+ab/4

then ab=800

The circumference of this rectangle = the circumference of the circle + 2 radii = 2 r + 2r = 2r ( +1) So, the radius is: cm)

Area: square centimeters).

1. The speed of the slow train is a km h, and the distance between the two places is x km.

Because: the express train travels a total of 680 kilometers in 8 hours, so the speed of the express train is 85km h in 5 hours, and the express train goes: 85 * 5 = 425 km then, the equation system:

3a+1 4x=425 5a+425=xSolve the system of equations: x=800

That is, the two places are 800 kilometers apart.

2. Let the length of the rectangle be x, the width be y, and the diameter of the circle be d

Then: 2(x+y)=

i.e. x = substitution into the equation x + y = d to obtain: (

Again: sin30°=y d=1 2

So d=2y

Substituting d=2y into , obtains: :( to solve yThen solve x, and then find the area of the circle according to r (the formula for the area of the circle).

The square centimeter of the rectangle = xy

Note: This solution should not be suitable for primary school students, unless it is an Olympiad class. I just used the solution of high school math to solve it.

Sorry! Hope the answer satisfies you.

I don't know the answer to the first question: Is 800 km correct?

ab The two places are 2,720 kilometers apart and square centimeters.

182-128) 6=9, the divisor is 9, the dividend is 128, 128 divided by 9 quotient 14 and the remainder is 2

The ratio of difference to subtraction is 3:5, then the subtraction is 3+5 8, and the subtraction is the number of wax wheels subtracted: 5 8

25*2 5*2 5 4 meters. Min Bureau Clan Bridge Cheats.

1. An enemy plane violated China's airspace, and our plane immediately took off to meet it. When the two planes were 50 kilometers apart, the enemy plane turned its nose and fled at a speed of 15 kilometers per minute, and our plane pursued at a speed of 22 kilometers per minute. When our plane chased it to a distance of 1 kilometer from the enemy plane, it engaged in a fierce battle with the enemy plane and shot down the enemy plane in only half a minute.

Q: How many minutes did it take for the enemy plane to escape from the time it began to be annihilated by our plane?

Solution: Time taken to pursue enemy aircraft = (50-1) (22-15) = 49 7 = 7 minutes.

A total of 7+1 2=minutes.

2. A is in city A, and B and C are facing each other at the same time in city B. A travels 6 kilometers per hour, B travels kilometers per hour, and C travels kilometers per hour. After it is known that A and B met, then A and C met. Find the distance between the cities A and B.

Solution: The distance difference of B C = (6 + km.)

The time when A and B meet = hours.

Then AB distance = (6 + km.)

3. A and B drive out of the two places at the same time, it takes 10 hours for line A to complete the journey, and it takes 15 hours for line B to complete the journey, and A travels 120 kilometers more than B when they meet. Find the distance between two places.

Solution: The speed ratio of A and B = distance ratio = the inverse ratio of time = 15:10 = 3:2

When they met, A went 3 5 and B went 2 5

So distance = 120 (3 5-2 5) = 600 km.

4. The cruise ship goes down the river, not 7 kilometers per hour, and goes upstream, 5 kilometers per hour, two cruise ships depart from the same place at the same time, and one of them goes down the river and returns; The other boat went up the river and returned, and after 1 hour, they returned to the starting point at the same time, asking how much time in this 1 hour did the two boats go in the same direction?

Solution: A boat that first goes downstream and then goes against the current, the speed of the downstream: the speed of the countercurrent = 7:5 = the inverse proportion of time (because the distance to and from the river is the same).

So his downflow time is 5 12 hours, and countercurrent time = 7 12 hours.

For boats that first go against the current and then go downstream, the time against the current = 7 12 hours, and the time against the current = 5 12 hours.

Then the time in the same direction = 7 12-5 12 = 1 6 hours.

5. The time it takes for a ship to sail 46 kilometers downriver and 34 kilometers against the current is exactly equal to the time it takes to sail 80 kilometers in still water. The speed of the current is known to be 2 km h, and the speed of the ship in still water is found.

Solution: Let the hydrostatic velocity be a kilometer hour.

46/(a+2)+34/(a-2)=80/a

80a-24)/((a+2)(a-2)]=80/a

24a=160

a = 20 3 km h.

1): minutes.

2): The distance between A and B and C when they meet is: kilometers.

So the time for A and B to walk before meeting is: (6+ so t=7 6 hours, so the total distance y=(6+km.)

3): From the question, it can be seen that the speed of A is times that of B, so the distance of line A is times that of B and the distance of the whole journey is 3 5, and the distance of line B is 2 5 of the whole journey 120 = 1 5 of the whole journey, so the whole journey s = 120 * 5 = 600 kilometers 4): Let the countercurrent time be x, and the downstream time is y, then: 5x=7y; x+y=1 gives x=7 12;y=5/12；Because the direction of travel is reversed at the beginning, the time leading to travel is t=x-y=1 6 hours, i.e. 10 minutes.

5): Let the sailing speed be x, then: 46 (x+2)+34 (x-2)=80 x

Solution: x=40 3

These questions are very simple、、Try to do a question to ensure that you will have a plenary meeting in the future。