There are 105 math problems in the first year of junior high school, and there are 10 answers

Xiao Ming takes the bus to school, which takes 30 minutes each way. If he goes to school once a day and goes home once, how much time does he spend on the bus each week?

In order to celebrate the 50th anniversary of the founding of the school, a sculpture with a height of 10 meters and a width of 5 meters was built on the campus. If the sculpture is a cuboid, then how many cubic meters of material are needed?

In a planar Cartesian coordinate system, what is the area of a triangle enclosed by a straight line y = 2x + 1 with the x-axis and y-axis?

A and B walked at a speed of 4 km and 6 km per hour respectively, and at the same time they started from A and B in opposite directions, a distance of 20 km. Excuse me, how long did it take for them to meet?

There are 45 desks in one classroom, each with 5 books and 3 pens. How many books and pens are there in this classroom?

In a supermarket, a carton of milk weighs 1 kg. If a bottle of milk has a capacity of 250ml, how many bottles of milk can be filled in a carton?

One region had a total population of 2 million last year, of which 51 percent was male and 49 percent was female. Excuse me, what was the male and female population of the region last year?

A rectangular river, 100 meters long and 20 meters wide. If 1 kg of feed needs to be fed per square meter of water surface, how many kg of feed does the river need?

A car travels at a speed of 80 kilometers per hour, stops for repair due to a breakdown after 2 hours, and continues to drive at 60 kilometers per hour after 2 hours of repair. Excuse me, how many kilometers did this car travel during the whole drive?

<> based on the content of the dialogue, please use the knowledge of equations to help the reporter find the age of the brother and sister

2.During the epidemic prevention and control period, masks have become an indispensable item in people's lives A mask factory has 87 workers, each of whom can produce 900 mask noodles or 1,100 mask ear cords per day, and one mask surface needs to be equipped with two ear cords

1) In order to make the mask noodles and mask ear cords produced every day just match, how many workers should be arranged to produce the mask noodles?

2) If the mask surface produced by the factory on a certain day happens to match the mask ear rope, and the cost price of a finished mask is a yuan, and the selling price is b yuan, please use the formula containing a and b to indicate the profit of the mask factory on that day

3.There are 84 workers in a workshop, with an average of 16 large gears or 10 small gears per person per day, and it is known that 1 large gear and 2 small gears are matched into a set.

A rectangular piece of paper, 12 centimeters long and 8 centimeters wide, fold it in half along one of the long sides to form a new rectangular piece of paper, how many centimeters are the new length and width?

A and B made a business in partnership, A contributed 4,000 yuan, B contributed 6,000 yuan, they earned 2,400 yuan in partnership, and distributed the profits according to the proportion of their respective contributions, how much yuan did A get?

A class of 30 students went on an outing, 20 boys and 10 girls, and boys made up a fraction of the class?

How long does it take to get from A to B on a highway that travels 400 kilometers from A to B and a car travels at a speed of 80 kilometers per hour?

How many buckets of paint do you need to brush a wall with 3 liters of paint if the area of a wall is 30 square meters? (Let's say a bucket of paint can be brushed 4 square meters).

Dig up a rectangular piece of soil at the bottom of a rectangle, 5 meters long, 3 meters wide, and meters deep, and the excavated soil can be filled with a new cuboid with a new length of meters, a width of 1 meter, and a height of 3 meters, asking how much volume does this new cuboid have compared to the original one?

There are 50 apples, to be divided among 10 people, how many can each person eat, if each person is asked to eat the same number of apples, how many can each person eat?

How many liters of fuel does a city need per day when it makes 3000 cars a day, based on the standard of 20 liters of fuel per car?

A supermarket carries out ** activity, the original price of a certain product is 120 yuan, and now it is discounted by 30%, how much is the ** after the discount?

A school has set up two elevators on the teaching building, elevator A runs at a speed of 3 meters and a speed of elevator B runs at a speed of 4 meters and seconds, if it takes 30 seconds to get from the first floor to the 12th floor, then how many floors should elevator A and elevator B stay on?

Ask, you haven't been to school!

A three is a number, the number on the single digit is 2 times the number on the ten, the number on the ten digit is the number on the hundred digit is less than 7, if the number on the hundred digit is exchanged with the number on the single digit, the resulting three-digit number is less than 1/2 less than the original 33, find the original three-digit number.

Solution: Let the three digits and hundreds be A, the ten digits be B, and the single digit C.

c=2b，a=b+7

Then the original three-digit number: 100 (b+7) + 10b + 2b = 112b + 700, and the replaced three-digit number: 100 * 2b + 10b + (b + 7) = 211b + 7

112b+700）/2-33=211b+7

Solution: b=2

c=2b=2*2=4

a=b+7=2+7=9

A: The original three-digit number was 924.

A stadium has a circular track of 400 meters, A runs 250 meters per minute on average, and B runs 290 meters per minute. If two people start from the same place and direction at the same time, how many minutes will it take?

Solution: (1) Suppose that two people start from the same place at the same time and meet after t minutes.

250+290）t=400

Solution: t=8 9

A: Now the two of them are starting from the same place at the same time, and they meet after 8 or 9 minutes.

2) If two people start from the same place and direction at the same time, they meet after t minutes.

290-250）t=400

Solution: t=10

Answer: If two people start from the same place and direction at the same time, they will meet after 10 minutes.

A and B typed the same manuscript, A typed an average of 120 words per minute, and B typed an average of 90 words per minute, and A finished the manuscript half an hour earlier than B.

Solution: It took X minutes for A and y minutes for B.

x+30=y

120x=90y

x=90

A: The manuscript is 10,800 words.

There are 70 people in a class, of which 52 can swim, 33 can skate, and 6 can't do both.

There are x people in the metropolis.

So those who can only swim have 52-x

people, there are 33-x people who can only skate.

52-x+33-x+6+x=70

x = 21 people.