2. There are several chickens and rabbits in the cage, which are *** 100 feet. If the chicken is replaced by a rabbit and the rabbit is replaced by a chicken, it will have 92 feet. How many rabbits and chickens are there in the cage?
Spiders have eight legs, dragonflies have six legs and two pairs of wings. Cicada has six legs, 1 pair of wings. At present, there are 18 of these three kinds of bugs, with 1 18 legs and 20 pairs of wings. How many bugs are there in each species?
4. In the activity of learning from Lei Feng, students * * * did 240 good deeds, senior students each did 8 good deeds, junior students each did 3 good deeds, with an average of 6 good deeds. How many students are there in this activity?
5. A class of 42 students participated in tree planting, with an average of 3 trees planted by boys and 2 trees planted by girls. As we all know, boys have 56 more trees than girls. How many boys and girls are there?
6. There are 2 15 students in the sixth grade of a school. 6% boys and 65,438+07 girls were selected to participate in the math competition held by the school, and the remaining numbers of men and women were just equal. How many boys are there in this grade?
7. Weight of two bags of rice * * * 182kg. If you take 8+0 out of bag A and put it in bag B, the two bags are equal in weight. How much do these two bags of rice weigh?
8. It takes 50 days for Party A and 75 days for Party B to process a batch of parts. Now they are working together, and B is on a business trip halfway, which takes 40 days to complete. A How many days did you do it alone?
9. In a sixth-grade math interest group in a school, girls accounted for 8/3, and then four female students were added. At this time, the number of girls just accounts for 9\4 of the whole group. How many people are there in the group now?
10. There is a batch of cloth several meters away. It takes three minutes. 4m to make a men's suit, 3. 2m to make a women's dress. If you make a suit for each male student, you will lose 6 yuan. 4 meters, and if you make a suit for each female classmate, it will be reduced by 2 meters. It is known that there are more boys than girls 1. How much cloth is there? How many boys and girls are there?
1 1. A theater has 20 rows of seats, the first row has 38 seats, and each row has 2 more seats than the previous row. How many seats are there in this theater?
12. Teacher Zheng bought 22 pens and brushes for 42.6 yuan, each with 2.7 yuan. 1 5 yuan. How many pens and brushes do you buy?
13. There are three grasslands with an area of 5 15 and 24 mu respectively. The grass on the grassland is as thick and grows as fast. The first grassland can feed 10 cows for 30 days, and the second grassland can feed 28 cows for 45 days. How many cows can eat on the third grass for 80 days?
14. There is a rectangular iron block in the cylindrical container. Now turn on the tap and pour the water into the container. In 3 minutes, the water surface is just above the top of the cuboid. Within 18 minutes, the container has been filled with water. It is known that the height of a container is 50 cm and the height of a cuboid is 20 cm. Find the ratio of the bottom area of a cuboid to the bottom area of a container.
15. Two cleaning vehicles A and B perform road cleaning tasks between East and West Cities. A cleaning alone takes 10 hour, and b cleaning alone takes 15 hour. Two cars leave from two cities at the same time. When we met, A cleaned more than B 12 kilometers. How many kilometers are the two cities apart?
16. 35 monkeys, big and small, went to pick peaches together. When the Monkey King is away, the big monkey can pick 15 kg in an hour and the little monkey can pick 1 1 kg in an hour. When the Monkey King is present for supervision, each monkey, regardless of size, can pick 65,438 monkeys per hour.
17. It takes 10.6 hours for the scientific experimental satellite launched by China to orbit the earth in the air for six weeks, and how many hours does it take to run 14 weeks?
18. 100 g of seawater for a salt drying field can dry 3 g of salt. According to this calculation, if you put 585,000 tons of seawater into a salt field at a time, how many tons of salt can you get out? How many tons of seawater can produce 9 tons of salt?
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