First, judge.

1. There are 8 boys and 10 girls in one class, with a male-female ratio of 0.8. ( )

2. Party A and Party B walk on the same road at the same time. Party A walks for 20 minutes and Party B walks for 30 minutes. The speed ratio of Party A and Party B is 2: 3. ( ? )

3. On the map with the scale of 8∶ 1, the line segment of 2 cm represents the actual length of the part of 16 cm. ( )

4. The perimeter ratio of the two circles is 2∶3 and the area ratio is 4∶9. ( )

Second, multiple choice questions

1. 24 yuan is charged for the fixed telephone first, and then the call charges are charged according to a certain standard time. Then, the monthly phone bill and call time (? )

A. proportional? B. inversely proportional? C. Proportional imbalance

Third, answer the application questions.

1. On the map, the length of 5cm represents the distance of 150km on the ground. Find out the scale of this map.

2. On the map with the scale of 1 ∶ 600000, the distance from A to B is 25 cm, and the actual distance between the two places is calculated. If a plane flies from Beijing to Nanjing at a speed of 750 kilometers per hour, how many hours will it take?

3. The composition of concrete is cement: yellow sand: stone = 1: 2: 3. Now it is necessary to pour 40 concrete floors, each weighing 0.3 tons. How many tons of cement, yellow sand and stones are needed as raw materials?

A ship, sailing from port A to port B, sailing at the speed of 25 kilometers per hour, can reach its destination within 8 hours. Return to Port A from Port B and sail 20 kilometers per hour. How many hours can it take?

A worker had to make 504 parts, and he made 120 in five days. At this rate, how many days will it take to finish the rest?

6, a hall, paved with square bricks with a side length of 6 cents, needs 324 pieces; If the square brick with a side length of 4 mm is replaced, how many bricks are needed?

7. A belt drives two wheels. The diameter of big wheel is 30 cm, and the diameter of small wheel is 10 cm. The small ship turns 300 revolutions per minute, and how many revolutions per minute does the big ship turn?

8. If 34 people need to work for 20 days to complete a project, how many workers are needed now if it needs to be completed three days in advance?

9, a literary book, read 6 pages a day, can be read in 20 days, 8 days in advance, how many pages more than the original every day?

10, woolen sweater factory * * * has 538 workers, divided into three workshops, the first workshop is less than the third workshop 12, and it is known that the ratio of the number of workers in the second workshop to the third workshop is 3: 4. How many people are in each of the three workshops?

1 1. The school allocates 60% of the books purchased to the fourth, fifth and sixth grades according to the ratio of 2: 3: 4. It is known that there are 56 books in grade six. How many books did the school buy?

12, Xiaoming stayed in four hospitals and paid 39.2 yuan for water last month, including two from Uncle Zhang's family, four from Grandma Wang's family, three from Aunt Li's family and five from Xiaoming's family. According to the population, how much do they each have to pay for water?

13, a production team harvested a piece of double-cropping rice by members of 15, which could have been harvested in 8 hours, but after cutting for 3 hours, due to the sudden change of weather, members of 10 were added to grab the harvest. How many hours will it take to cut this piece of double-cropping rice?

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