Elementary math application questions, urgent! There must be a problem solving process!

Hello! My method is:

1.Let the original minus be a and the original minus be b.

a+5)-(b-60)=234

a-b+65=234

a-b=169

2.Now there are 180 3 60 in each basket.

The original third basket had 60 (1 1 4) 80 and the original second basket had (60 80 1 4) (1 1 3) 60, and the original first basket had 180 80 60 40.

3.On the 6th day before eating there were 12 2 24 pcs.

There are 24 (1 1 3) 36 before eating on the 5th day, 36 (1 1 4) 48 before eating on the 4th day, 48 (1 1 5) 60 before eating on the 3rd day, 60 (1 1 6) 72 before eating on the 2nd day, then there are 72 (1 1 7) 84 peaches in this pile.

Essence (on your own paper):

1.A round bar with a cross-sectional diameter of 2dm, after being formed into two sections, the sum of the surface area of the two sections is a square decimeter, what is the volume of the original round bar?

2.There are several two-wheeled motorcycles and four-wheeled cars parked in the garage, and the ratio of the total number of vehicles to the number of wheels is 2:5What is the ratio of the number of motorcycles to the number of cars?

3.The circumference of the two rectangles A and B is equal, and the length-to-width ratio of the A rectangle is 3; 2. The ratio of the length and width of the B rectangle is 7:5, so what is the ratio of the area of the two rectangles A and B?

4.In a test conducted by a foreign Chinese school, the average score of the boys in class 63 was 90 points, the average score of the girls was 92 points, and the average score of the whole class was 92 points.

Elementary Mathematics Application Questions:

Solution: From the title, there are 64 25%=16 black rabbits, and 64-16=38 white rabbits.

Set to buy black rabbit x only, then.

x+16) (x+64) 100%=40% gives x=16

A: I bought another 16 black rabbits.

Arithmetic method:

It turned out that the black rabbit accounted for 1 4 of the total and was 16 individuals.

Then, the white rabbit accounts for 3 4 of the total and is 48 individuals.

After buying some black rabbits, black rabbits account for 2 5 of the total, then, white rabbits account for 3 5 of the total, because there is no white rabbit to buy, so, the number of white rabbits has not changed, so, 48 corresponds to 3 5, then, now there are a total of 48 3 5 = 80, 80-64 = 16. So, I bought 16 black rabbits.

The law of the equation is like "zhenxiai168" said, there used to be a black rabbit = 64 * 25% = 16, let the buy x black rabbit, there is (16 + x) (64 + x) = 40%.

Solution x=16

In the past, Black Rabbit = 64 * 25% = 16, set to buy x Black Rabbit, there is (16 + x) (64 + x) = 40%

Solution x=16

The black rabbit has 64 25%=16, the white rabbit 64 75%=48, after buying the black rabbit, the black rabbit accounts for 40% but the number of white rabbits has not changed, that is, the white rabbit accounts for 60%, so after buying the black rabbit, there is a total of 48 60%=80, so the black rabbit has 80-48=32, so buy 32-16=16 black rabbits.

Kids, this question is not difficult at all.

Set and buy the black rabbit x and get:

16+x) (64+x)*100%=40% Find x=16

C rests for 2 days, B has to do 4 more days, B and C efficiency ratio 1 4:1 2 = 1:2 B does 4 days, which is equal to A and B cooperation for one day, A and B efficiency ratio (4-1): 1 = 3:1 so A: B: C = 3:1:2

A needs to do it alone: 13 [3 (3+1+2)]=26 days A 1 + B 1 = B 4 = C 2

A1 = B3 B13 = A13 3

C1 = B2C13=B26

B26=A26 3

This project is required by A alone:

13 + 13 3 + 26 3 = 26 (days) A, B, and C do this project every day 1 13 If C rests for 2 days, B will do 4 more days, that is, C does 2 times as much as B every day.

If C rests for 2 days, A and B do more than 1 day together, that is, B does 1 2 of A and B every day, which is A.

B C does 1 3 every day, so C does this project every day (1 13) * (1 3) = 1 39

B does (1 39) 2=1 78 per day

A does 1 13-1 39-1 78 = 1 26 a day A needs 1 (1 26) = 26 (days) to do alone

Let the amount of work to be completed per day: A is A, B is B, and C is C, then the total workload is 13*(A+B+C).

According to the title, there are:

2c=4b2c=a+b

Solution: c=2a 3

B=A3, then the total engineering quantity is 13*(a+b+c)=13*(A+2A3 +A3)=26A

Therefore, it takes 26a a=26 days for this project to be done by A alone.

From the title, we know that C does 2 days = B does 4 days = A and B cooperate for 1 day.

From: C does 2 days = B does 4 days to get the ratio of C: B = 4:2 = 2:1 From: B does 4 days = A and B cooperate for 1 day The ratio is B: A B = 1:4, then B: A = 1:3

C rests for two days and B does 4 more days, indicating that C's 2-day workload is 4 days of B, and A and B's cooperation for one day means that C's 2-day workload is the sum of A's one-day workload, so if B's one-day workload is x, then C's one-day workload is 2x, and C's 2-day workload minus B's one-day workload is A's one-day workload, that is, 2*2x-x=3x is A's one-day workload, so A, B, and C's one-day workload is x+2x+3x=6x, and the total workload = 6x*13 days=48x, so A alone needs 48x 3x=16 days.

1. If car A travels x kilometers per hour, then car B travels kilometers per hour (solution: x=40

2. Set this barrel of oil x kilograms.

x 20% x 4= solution: x = 7

3. This question examines the knowledge of the least common multiple, a row of 6 people or a row of 8 people is exactly full and there is no one left, which means that the number of people in this class is a common multiple of 6 and 8, and there are about 50 people in the preparatory (1) class, so the number of people in this class is 48 people.

1. After hours, car B travels 70 kilometers more than car A, and car B travels more than car A per hour

70 km/h, the speed of car B is twice the speed of car A, then car B is twice as fast as car A, then the speed of car A is 20 km/h.

Or the equation calculates, let the speed of car A be x kilometers per hour, then the speed of car B is kilometers per hour, and the equation is as follows

When solving the equation to get x = 40 km.

2. After the first use of 20%, there is 80% left, and the second time 4 kg is used, and the remaining kilogram is known, it can be seen that 80% of the weight of this barrel of oil is 4+ kilograms, kilograms, and this barrel of oil weighs 7 kilograms.

Or the equation calculates, let the barrel of oil weigh x kilograms, then:

x-x*80%-4=, solve the equation x=7 kg.

3. This question should be to find the common multiple of 6 and 8, and see that the common multiple is close to 50. It should be 48 people.

Column equations, you can set a total of x students in this class, then:

x 6 = 8, solution x = 48 people.

1. The distance traveled by car B per hour is times that of car A, then at the same time, car B travels twice the distance more than car A 70 is the road that car A travels more per hour, it is a time of the speed of car B, and 70 is the speed of car B 70

2. There is 80% after the first use

4+3, find the common multiple of 6 and 8, and about 50.

24,48,,, of course 48

1.Solution: If car A travels x kilometers per hour, then vehicle B travels kilometers per hour.

Solution x=40

A: Car A travels 40 kilometers per hour.

2.Solution: Let's say that this barrel of oil weighs x kilograms.

1-20%)x-4=

Solution x = 7 Answer: This barrel of oil weighs 7 kilograms.

3.Solution: According to the title, this number should be a common multiple of 6 and 8, and within 50.

This number is 48

A: There are 48 students in this class.

1 You should learn the equations.

Let the driving speed of the armored vehicle be x

x=？2 Let the total be x kilograms.

x=73 Don't know.

Think about it.

Let's set A as x first, because car B travels twice as far per hour as car A, and the two cars meet after hours, and when they meet, the car has traveled 70 kilometers more than car A.

Solution: It can be known from the meaning of the title:

1000x+10y+z=9 (100x+10y+z), 100x=80y=8z, 25x=20y+2z, so x is even, z=0 or 5, when x=2, z=5, y=z, the number is: 225;

When x=4, z=0, y=5, the number is 450;

When x=6, z=5, y=7, the number is: 675;

When x=8, the requirements are not met

A: The drugs were hidden in boxes marked with a mysterious number

From the meaning of the title, we know that 1000x+10y+z=9 (100x+10y+z), 100x=80y=8z, 25x=20y+2z, so x is even, z=0 or 5

1000x+10y+z=9 (100x+10y+z), 100x=80y=8z, 25x=20y+2z, so x is even, z=0 or 5, when x=2, z=5, y=z, the number is: 225;

When x=4, z=0, y=5, the number is 450;

When x=6, z=5, y=7, the number is: 675;

When x=8, the requirements are not met

A: The drugs were hidden in boxes marked with a mysterious number

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The speed of car A is 1 (5-4) 4=4 km/h.

The speed of car B is 4+1=5 km/h.

At the time of the encounter, both cars A and B drove 5 5 = 25 kilometers.

Car A traveled 25 4=hours at the time of the encounter.

Car A starts an hour earlier than the loss of car B).

The comprehensive column formula is.

hours) I wish you a happy day.

A speed = 1 (5-4) 4 = 4 kilometers in the time of the small state clearing.

B speed = 4 + 1 = 5 thousand spring meters hours.

B travels = 5 5 = 25 km.

A early departure = 25 4-5 = hours before the book.