Very anxious 6th grade math problems. Please write out the steps. Thank you.

Let A be x, B be y, and C be z

x+y=36 y+z=45 z+x=60

1) x=60-z; 60-z+y=36

2) y-z=-24 y+z=45

3) y=z-24

4) z-24+z=45 2z=69 z=5) x=60-z= So it takes 25 and a half days for A himself.

A + B = 36 A + C = 60 A + B + A + C = 96 B + C = 45

A + B + A + C - (B + C) = 96-45 = 51 = A + A.

A = day.

x+y=36

y+z=45

z+x=60

The solution is x=y=z=

So A needs days.

A + B = 36,—— B = 36 - A.

A + C = 60,—— C = 60 - A.

B + C = 45,—— 36 - A + 60 - A = 4596 - 2 A = 45

2 A = 51 A = days.

Set armor. Second. C takes days to complete respectively, and there is the following formula:

1 x+1 y=1 36 Equation 1;

1 y+1 z=1 45 Equation 2;

1 x+1 z=1 60 Equation 3;

From the above three formulas, x=...

Do the math for yourself.

Assuming that the number of Zhang Chan Cong of 20 yuan, 50 yuan, and 100 yuan is x, y, and z respectively, you can get a blind argument equation grinding and attacking the waiter group:

x+y+z=50

x=y20x+50y+100z=2400

Solve it out and get it.

x=y=20

z=10

Let 20 yuan have x sheets, then 50 is x, 100 is (50-2x), and the equation of the column trembling Ling gets: 20x+50x+100(50-2x)=2400, ==x=20So, 20 yuan for the mountain and 50 yuan for 20 sheets, 100 yuan for 10 sheets, Wang.

64 1 17 9 + (13 2 11 + 11 2 13) (5 11 + 5 13).

1089 17 9+ (13 2 11 + 11 2 13) (5 11 + 5 13).

121+(13+2 11+11+2 13) (5 11+5 13).

5 May 2003 2007

35 6-49 12+63 20-77 30+91 42-105 56)-1 and 3 8] 1 8

(35 6-49 12+63 20-77 30+91 42-105 56)-1 and 3 8] 8

1) 6 12:18 = 1:1, then 30 plus 60 original ratio is true, or 90 minus 60 original ratio is also true.

2) 6 3 = 2, area = square centimeters.

3) 5m = 500cm, 500x1: 500 = 1cm, area = ur 2 = 4), 3x3000 = 6000cm = 60m, area = 60x45 = 2700m 2

An increase of 12 is an increase of 12 6 = 2 (times), so 30 and 90 should also be increased by a factor of 2:

30+30*2=90 90+90*2=1802.The size of the bedroom pictured on the map is x square centimeters.

x=6/3*（

x = 2 * x = m = 500 cm.

The area on the drawing is x centimeters.

x=（500*500/500）^2*

x=5*5*

x = cm) = 45 (m) (the height of the distance from cm on the map is the actual distance of 45 m) 3 1 * 3000 = 9000 (cm) = 90 (m) (the bottom is the same) 45 * 90 = 4050 (m 2).

The first question uses an equation.

Hope it helps.

1:30 becomes 20 and 90 becomes 30

2:1 cm means 3 meters, then there is a scale of 1:300, so the length of the bedroom on the picture is:

The relief x on the 2 cm map has: x:480=1:

300, get x = cm 3: the original area of the flower bed is: s =, the area on the map is x, which is obtained by the scale:

x:s=1:500^2

Calculate x and you'll get the answer.

4: The area of the parallelogram on the figure is: , let the original area be s, which is obtained from the scale::s=1:3000 2

Calculate s to get the answer.

Change 60, both add 2 times the molecule.

4. square meters.

1. Xiao Ming made 1 3, and then made the remaining half, that is, (1-1 3)*1 2=1 3, that is, when he did a total of 2 3, Xiao Hua did 1 2, so their speed ratio is 2 3:1 2=4:3.

And when Xiao Ming did 1 3, Xiao Hua should have done 1 3 * 3 4 = 1 4, at this time he still had 45 questions left, and the socks he pointed to were divided by 45 (1-1 4) = 60 questions, and the two of them did the same number of questions, adding up to a total of 120 questions.

2. From the meaning of the title, there is 11 m=, that is, mn=30, because 9 n<5, that is, n>9 5, because it is a natural number, so n>=2, so the combination of m and n has 6 groups: 15 and 15. They are the sum of the bushes that are sold and are respectively.

The third question should have a picture, because you can't see the picture, so you can't do it.

1. This question should grasp a key point: the time they take is the same. The total number of questions is A, Xiao Ming did 1 3A in the first period of time, and Xiao Hua did A-45.

In the second time period, Xiao Ming did the remaining half of 1 3a, and Xiao Hua did exactly half of 1 2a-(a-45). So the first.

In the first and second time, Xiao Ming did 2 3a, and Xiao Hua did 1 2a, because the speed ratio of time is the same.

At one and two o'clock, the ratio of the amount done in the cave is 4:3. According to the equation that the second period is the same, can be listed and withered: t=1 3a 4=[1 2a-(a-45)] 3, a=60 can be calculated, and the two of them do a total of 2a=120 friends.

Method 1:

Solution: Let the original red ball 19a, white ball 13a, then the number of red balls put in for the first time is 13a 5 3-19a=8a 3, at this time the red ball is 65 3a, the white ball is still 13a, and the number of white balls put in is 65a 3 11 13-13a=16a 3 The red ball put in is 80 less than the white ball put in, 16a 3-8a 3=80 solution: a=30 There are a total of balls in the original bag:

30 (19+13)=960 (pcs) Answer: There were 960 balls in the original bag.

Method 2: Solution: The original ratio of the number of red balls to white balls in the bag is 19:13, and after putting in a number of red balls, the ratio of the number of red balls to white balls becomes 5:

3. At this time, the white ball has not changed, and we can distinguish the ratio of the original white ball to the current red ball: Original: 57:

39 Now:65:39 At this time, the red ball added:

65-57=8 (portions) Again, the red ball was added later, and then the score was passed: Original: 65:

39 Now: 65:55 The white ball is added:

55-39 = 16 (parts) then white is 8 more parts than red, divide 80 by 8 = 10, one is 10, multiply 10 by (57 + 39) = 960 (pieces) Answer: There were 960 balls in the original bag.

Original Red Ball: White Ball = 19:13 = 57:39

After adding the red ball, the red ball: white ball = 5:3 = 65:39 and then the white ball, red ball: white ball = 13:11 = 65:55 set the original red ball 57x, white ball 39x.

The red ball (65-57) x = 8x is added first.

Add white balls (55-39) x = 16x.

By the title, 16x-8x=80

solution, x=10

So, it turned out that there were 570 red balls and 390 white balls in the bag.

Red: White = 19:13, how can there be 80 less. Written wrong, right?

1.The area of the rectangle is reduced by 20cm, for the time being, the cut is seen as a rectangle, and the width of this rectangle is 4cm, 20 4 = 5cm, and the length of this rectangle (the width of the whole rectangle) is 5cm. The length of the cut rectangle is not removed from the width of the rectangle that is 4cm long, and the length of the remaining square is 5cm, 5 5 + 20 = 45cm.

2.Since the introverted product is equal to the extroverted product, condition: an outer term is 20% of this product, from which two extroverts can be calculated: 34 20%=

The product of the two extroverts is and 5, and the product is 34

So the ratio is::2=17:5

3.In fact, the width of this rectangle is the radius of the circle. In this way, one length of the rectangle is half of the circumference of the circle, and of course the two lengths are the circumference of the circle, and the circumference of the circle is: 2

The circumference of the r rectangle can be columnar as: 2

r2r= is. Derived. r

2 The answer is 4He said that the lower half of the bottle is a cylinder, so after filling the water, the bottle is turned upside down, and the water is 6 cm high, 8-6 = 2 cm

At this time, the upper end of the bottle is also empty with a cylinder 2cm high, and this empty volume can be calculated:

6×2=12cm³

The empty ones are calculated, and then the volume of water is added to the volume of the bottle:

12+6×4=36cm³

Theft is prohibited downstairs.