2. A school has 662 teachers and students. Male athletes account for116, and female athletes account for 7/57, as many as male students. How many students are there in this school?
For a pool, it takes 50 minutes to fill the empty pool with a pipe and 60 minutes to drain the pool with a pipe. If the two sides are parallel, how many minutes will it take to fill the empty pool?
4. Party A and Party B cooperate on a batch of parts, which can be completed in 8 days. If A does it alone for 20 days, how many days does B do it alone?
5. Two bags of soybeans, the weight of bag A is 5/8 of that of bag B. Take out 6 kg from bag B and put it into bag A, and the weight of two bags of Huang Dou is equal. How much did these two bags of soybeans weigh?
6. A pile of wheat, if you remove 3/8, there are 3.5 tons left. If you remove 5/9, how many tons are left?
Answers to questions 3, 4, 5 and 6:
3. Solution: Let the water in the pool be X liters, then the speed of A is x/50 (liter/minute) and the speed of B is x/60 (liter/minute).
Therefore, the time required for parallel operation is: x/[(x/50)+(x/60)] = 300/11(minutes) =27.3 (minutes).
A: It takes 27.3 minutes.
4. Solution: Let A do X every day and B do Y every day.
Then there is the equation: 8(x+y)=20x, and the simplified equation: 8y= 12x. Multiply both sides of the equation by 20/ 12, and you can get the equation: 40y/3=20x, that is, it takes 40/3=~ 13 days for A to be completed in 20 days.
A: B It will take about 13 days to complete.
5. Solution: If the weight of B is X kilograms, the weight of A is 5x/8.
According to the meaning of the question, x-6=5x/8+6 can be interpreted as: x=32 (kg), 5x/8=20 (kg).
Answer: A bag is 20kg, and B bag is 32kg.
6. Solution: 3/8 has been shipped, leaving 5/8, that is, 5/8 is 3.5 tons.
3.5/(5/8)=5.6 (ton), of which 5/9 has been shipped, leaving 4/9.
5.6*4/9=2.49 (ton) is approximately equal to
A: There are 2.49 tons left.
1. There are two barrels of oil, A and B. After pouring from barrel A 1/3 to barrel B, pour from barrel B 1/5 to barrel A. At this time, two barrels of oil each have 24 kilograms. How many kilograms are there in two barrels of oil, A and B?
2. It takes Party A and Party B 6 days to complete a project, and Party B and Party C need 10 days ... Now Party A, Party B and Party C have cooperated for 3 days, and Party B has just finished the remaining 6 days. How many days does it take to complete this project alone?
It takes Party A 6 minutes, Party B 5 minutes and Party C 4.5 minutes to manufacture a part. At present, there are 1590 parts, which are assigned to three of them and are required to be completed at the same time. How much is each of Party A, Party B and Party C?
The fuel carried by the plane can fly for up to 6 hours. When flying out, you can fly with the wind at a speed of 1.500 km, and when flying back, you can fly against the wind at a speed of 1.200 km. How many kilometers should this plane fly back at most?
Answer: 1. Let a barrel of crude oil be X kg and b barrel of crude oil be Y kg.
(x/3+y)/5+2x/3=24
(x/3+y)(4/5)=24
solve
x=27
y=2 1
2. set a efficiency x B efficiency y C efficiency z
6(x+y)= 1
10(y+z)= 1
3(x+y+z)+6y= 1
solve
x= 1/9
y= 1/ 18
z=2/45
3. According to the meaning of the question, the efficiency of A is 1/6, that of B is 1/5, and that of C is 1/4.5.
Let a be divided into x, b into y and c into z.
x+y+z= 1590
6x=4.5z (equal time, time = total amount/efficiency (e.g. x/( 1/6)=6x))
6x=5y
solve
x=450
y=540
z=600
4. Set the maximum flight distance to x kilometers.
x/ 1500+x/ 1200=6
x=4000
(distance/speed (such as x/ 1500)= time (6 hours))
When Xiao Ming calculated 15/2+65 ×), he calculated 15/2+65 by mistake. The result of this calculation is nine thirds less than the correct answer. What's the number in ()?
Answer: (15/2-9/2)/(15/2) = 2/5.
The number in () is 2/5.
Sorry, I'm only in the sixth grade, but my knowledge is good. I think this problem is how to do it! ! ! ! Hmm. How interesting
1. Cut a circular piece of paper into two sectors, A and B. If the area of A is 18 cm2 and the area of B is 12 cm2, the central angle of sector A is _ _ _ _ degrees greater than that of sector B. 。
2. Xiao Zhang has a semicircular piece of paper with a diameter of 10 cm. He cut out a circle as large as possible, so what is the area of the rest of the paper? (accurate to 0.0 1 cm2)
3. Enlarge the radius of a sector to three times, and reduce its central angle to half at the same time, so that the area of the new sector is increased by 70 square centimeters. Find the area of the original sector.
4. A stadium with a length of 80 meters and a width of 80 meters, both ends of which are semicircles with a diameter of 80 meters, how many square meters of land does it take to open eight circular runways with a width of 0.85 meters outside?
Answer: (1)72
(2) The area of the original semicircle is (10/2) 2 * pi =12.5 * pi.
Subtracting the area of the largest circle is (5/2) 2 * pi = 6.25 * pi.
So the remaining area =12.5 * pi-6.25 * pi = 6.25 * pi = 6.25 * 3.14 =19.63.
(3) 3 2/2 = 4.5 means that the changed area is 4.5 times of the original, that is to say, it is increased by 3.5 times.
70/3.5=20
So the original area is 20 square centimeters.
(4) 0.85 * 8 = 6.8m
The original area is 80 * 80+3.14 * (80/2) 2 =11424 (square meter).
The total area of the runway after opening is (80+2 * 6.8) * 80+3.14 * (80/2+6.8) 2 =14365.3536 square meters.
Therefore, the land area is14365.3536-11424 = 2941.3536m2.
Well, that's all.