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For a project, it takes a day for Party A to finish it alone, and it takes B day for Party B to finish it alone. For Party A and Party B to cooperate for 5 days, how many parts of the project can be completed? Regard the project as unit 1
The speed of a is 1 / A, the speed of B is 1 / B, the speed of cooperation is (1 / A + 1 / b)
Therefore, 5 (1 / A + 1 / b) = 5 (a + b) / AB can be completed after 5 days of cooperation
1. Xiao Ming asked the teacher how old he was. The teacher said: when I was your age, you were just 3 years old. When you were my age, I was 33 years old. How old is Xiao Ming?
2. There are 23 two wheeled motorcycles and three wheeled motorcycles in the parking lot. Lele counts that these motorcycles have 60 wheels in total. How many two motorcycles and three wheeled motorcycles are there in the parking lot?
3. A middle school library bought three hardcover and five ordinary Chinese dictionaries, which cost 27.8 yuan. If one hardcover is used to exchange two ordinary Chinese dictionaries, one more yuan will have to be paid. How much is each hardcover Chinese dictionary?
4. The school bought 6 tables and 8 chairs and paid 477.6 yuan in total. Each table is 34.8 yuan more expensive than each chair. How much is each table and chair?
1. 33-3 = 30 (years old) 30 / 3 = 10 (years old) 10 + 3 = 13 (years old)
2. 23 * 3 = 69 (pieces) 69-60 = 9 (pieces)
Two wheeled motorcycle: 9 / (3-2) = 9 (units) three wheeled motorcycle: 23-9 = 14 (units)
3. (27.8 + 3 * 1) / (3 * 2 + 5) = 2.8 (yuan) 2.8 * 2-1 = 4.6 (yuan)
4. Chair: (477.6-34.8 * 6) / (6 + 8) = 19.2 (yuan) table: 19.2 + 34.8 = 54 (yuan)
For a cylinder and a cone, the ratio of base circumference is 2:3, and their volume ratio is 5:6
A． 8：5 B． 12：5 C． 5：12 D． 5：8
The first term of a ratio is 80% of the second term, which is five times of the ratio
If you add a 0 to the middle of a two digit number, the resulting three digit number is 9 times the original number, then the original number is ()
The sum of the simplest fractions of a and B is 1115, the ratio of the denominators of a and B is 3:5, and the numerator of these two numbers is ()
There are 84 people in class A and class B, 58 in class A and 34 in class B, 57 in total
The total length of a highway is 60 km, which is divided into three sections: uphill, level road and downhill. The length ratio of each section is 1:2:3, and the time ratio of Uncle Zhang's riding through each section is 3:4:5. It is known that his riding speed on level road is 25 km per hour. How long did it take him to complete the whole journey?
There are too many questions,
There is a granary, which first transports 33 tons of grain less than 2 / 5 of the total grain storage, and then transports 143 tons. At this time, the grain storage in the granary is 15% higher than the original. How many tons of grain were stored in the granary?
The ratio of the circumference of the bottom surface of a cylinder and a cone is 2:3, and the ratio of their volume is 5:6. The simplest integer ratio of the height of a cone and a cylinder is: (b) a.8:5 b.12:5 c.5:12 d.5:8. The former term of a ratio is 80% of the latter term, which is 5 times of the ratio. The simplest ratio is (4:5)
RELATED INFORMATIONS
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