Problem solving and answers for 5th grade book

1, a rectangular sand pit, 4 meters long, 2 meters wide, 0.5 meters deep, if each cubic meter of yellow sand weighs 1.4 tons, how many tons of this yellow sand weighs?2, a rectangular tin water tank, 18 decimeters long, 10 decimeters wide, known that this tank can hold up to 1620 liters of water, how deep is this tank?3, a rectangular plastic box of potion, the inside is 0.6 meters long, 0.25 meters wide, 0.5 meters deep. 0.5 m, if this whole box of potion into each bottle can be loaded 400 ml of vials, the box of potion at least how many bottles?4, a square billet prism length of 6 decimeters, forging it into a cross-section is the side length of 3 cm square rectangular steel, steel length of how many meters?5, a rectangular oil drum, the bottom area is 18 square decimeters, which can be loaded with 43.2 kg of oil, if the oil weighs 0.8 kg per liter, the height of the oil drum is 0.8 kg, the oil drum is 0.8 kg, the height of the oil drum is 0.8 kg, the oil drum can be loaded with 1,000 kg, the oil drum can be loaded with 1,000 kg. kg, the height of the barrel is how many decimeters?6, in a 25 cm long, 20 cm wide glass cylinder, there is a prism length of 10 cm square iron block, the water depth of 15 cm, if the piece of iron from the cylinder out, the cylinder in the depth of how many centimeters?7, a rectangular tank, the bottom is a square, from the inside of the measurement of the length of the side is 6 decimeters. Inside has been 144 liters of oil, known inside the depth of oil is half the depth of the tank, this tank is how many decimeters deep?8, a room *** paved 1200 pieces of 40 cm long, 20 cm wide, 2 cm thick wooden floor, this room **** covers an area of how many square meters? How many cubic meters of wood are needed to pave this room***?9. A section of rectangular steel, 1.6 meters long, has a cross-section that is a square with sides 4 centimeters long. Each cubic centimeter just weighs 7.8 grams, how much does this piece of square steel weigh?10. How many square decimeters of iron are used to make a rectangular oil drum without a lid, 4 decimeters long and wide and 6 decimeters high? Put gasoline in the barrel, each liter of oil weighs 0.82 kg, this barrel can hold how many kilograms of gasoline?11, a prism length is 0.6 m square billet, forged into a cross-section is 0.09 square meters of rectangular steel, forged steel how long? (Use the equation to answer.) 12, a rectangular glass cylinder, measured from the inside of the length of 40 centimeters, width of 25 centimeters, the depth of water in the cylinder is 12 centimeters. After dipping a stone into the water, the surface of the water rises to 16 cm. find the volume of the stone.13. To make a 12-section rectangular tin chimney, each section is 2 meters long, 4 decimeters wide, and 3 decimeters high, at least how many square meters of tin will be used?14. The floor of Xiao Min's room is rectangular. It is 5 meters long and 3 meters wide, with a 2 cm thick wooden floor, at least how many cubic meters of wood are needed?15, a coal truck measured 2.5 meters long and 1.8 meters wide from the inside, and loaded with coal that is 0.6 meters high, and weighs an average of 1.5 tons of coal per cubic meter, how many tons of coal were loaded in this truck?16, a kind of rectangular shaped tin bucket without a lid, with a base that is a square with a 4-decimetre side length, and a height of 1 metre. How much tin does it take to make one such bucket? How many liters of water can this bucket hold?17. A stadium is paved with 37.5 cubic meters of cinder blocks on a straight track 100 meters long and 7.5 meters wide. How thick can the cinder blocks be laid?18. A rectangular shaped children's swimming pool is 40 meters long, 14 meters wide and 1.2 meters deep. How many square tiles with an area of 16 square decimeters are needed to be applied to the four walls and the bottom of the pool?19. A rectangular container with a bottom area of 16 square decimeters is filled with water that is 6 decimeters high, and is now put into an iron block with a volume of 24 cubic decimeters. What is the height of the water at this point?20. A rectangle is formed by stacking 2,100 squares with an edge length of 1 centimeter, which is 10 centimeters high, and whose length and width are greater than its height. What is the perimeter of its base? 21, A rectangular piece of tin, 32 cm long, has a square with a side length of 4 cm cut off at each of its four top corners and then folded and welded into a rectangular tin box without a lid. The volume of this tin box is known to be 768 cubic centimeters. What is the area of the original piece of tin? 22, the area of a rectangle is 24 centimeters, its length and width are whole centimeters, how many kinds of such rectangles? 23, five (1) class of no more than 50 students, group cooperative learning, depending on the content of the different can be divided into each group of 3, each group of 4, each group of 6, each group of 8 people, all kinds of division are just divided up. This class may have students () or (). 24, A, B, C three people to the library to borrow books, A every 6 days to go once, B every 8 days to go once, C every 9 days to go once, if March 5, three of them met in the library, then the next time they all go to the library is how many months and how many days? 25, gardeners in a section of the highway on both sides of the tree planted at intervals of 4 meters, a **** planted 74 trees. Now they want to change to plant a tree every 6 meters. How many trees do not need to be transplanted?26. Uncle Zhang sold fruit all day, and when he counted the money in the evening, he realized that the stack of bills in his hand was some 2 yuan and 5 yuan. Uncle Zhang divides the stack into two equal piles, with an equal number of five and two dollar bills in the first pile, and an equal number of five and two dollar bills in the second pile. Do you know at least how many yuan of this stack of bills?27. Bright Elementary School fifth-grade students, divided into groups of seven, eight or six people in line to do exercises, are exactly divided, at least how many students in the fifth grade?28. A rectangular tank filled with 60 liters of medicine, known inside the tank is 5 decimeters long and 3 decimeters wide, how many decimeters deep is it?2. A room is 6 meters long, 3.5 meters wide The height of the room is 3 meters, and the area of the windows and doors is 8 square meters. How many square meters is the area of the room to be painted with cement? If each square meter needs cement 4 kg, a *** to cement how many kilograms? 29, a car from A to B, set off 5 hours line 225 kilometers, according to this calculation, and then line 3 hours to reach B, A and B distance between the two places is how many kilometers? 30, two classes of fifth-grade students from the library a *** borrowed 486 books, an average of 6 borrowed per person, known as the first class of 40 students, the second class should be how many students? The second class should be how many students? 1: sports supplies have 90 ping-pong balls, if every two boxes, can exactly loaded? If you put one box for every five, can you fill them all up? Why?90#2=45 boxes90#5=18 boxesAnswer:If you fill one box for every two, you can fill them all.If you fill one box for every five, you can also fill them all. Because 90 can be divided by five.2: The sports store has 57 balls, every three in a box, can be exactly loaded?57#3+19 boxesAnswer: can be exactly loaded.3: A, B, two people to type a 10,000-word document, A per minute to play 115 words, B every minute to play 135 words, how many minutes can be typed?10,000 # (115 + 135) = 40 minutesAnswer: 40 minutes can be typed.4: A, B, two people to type a 10,000-word document, A per minute to play 115 words, B every minute to play 135 words, how many minutes can be typed? 4: fifth-grade students planting trees, 13 or 14 people in a group are exactly divided, fifth-grade students to participate in tree-planting at least how many people? 13X14 = 192 people Answer: fifth-grade people to participate in tree-planting at least 192 people. The following questions are application questions, but they are related to equations. I used equations to solve them.5: Two cars are traveling back-to-back from one place to another. One car travels 31 kilometers per hour and the other travels 44 kilometers per hour. After how many minutes are the cars 300 km apart? Equation: Solution: Two cars meet after X hours.31X+44X=30075X=300X=44 hours=240 minutesAnswer: After 240 minutes the two cars are 300 kilometers apart.6: Two teams of engineers have to *** with digging through a 119-meter-long tunnel, the two teams from the two ends of the construction respectively. Team A dug 4 meters per day, team B dug 3 meters per day, after how many days to dig through the tunnel? Solution: X days after digging through the tunnel 3X + 4X = 1197X = 119X = 17 Answer: After 17 days to dig through the tunnel.7: school chorus and dance team **** 140 people, the number of chorus team is 6 times the number of the dance team, the dance team, how many people? Solution: The dance team has X people 6X+X=1407X=140X=20Answer: The dance team has 20 people. From here on it's not an equation problem.8: Two brothers go from their home to the gym at the same time, and the road is 1300 meters long. The brother walked 80 meters per minute, the brother rode a bicycle at a speed of 180 meters per minute to the stadium immediately after the return, on the way to meet with the brother, this time the brother walked a few minutes?1300X2 = 2600 meters 2600 # (180 + 80) = 2600 # 260 = 10 minutes Answer: This time the brother walked 10 minutes.9:: June 1 Children's Day, Mr. Wang bought 360 cookies, 480 pieces of sugar, 400 pieces of fruit. Sugar, 400 fruits, the production of exquisite small gift packages, distributed to children as gifts, up to do a few small gift packages?360 + 480 + 400 = 1240 Answer: up to do 1240 small gift packages.10: naughty to buy 40 balloons, invited students to the home than to blow up the balloons. In order to divide the balloons equally, how many students should naughty ask to blow up the balloons? 淘气不参加.40#2=20人40#4=10人40#5=8人40#8=5人40#@0=4人40#20=2人答:请同学的方法有6种,分别是:20人,10人,5人,8人,4人,2人.11:一块梯形的玉米地,上底15米,下底24米,高18米. How many corn plants can be planted in a plot of land with an average of 9 corn plants per square meter? (15+24)X18#2=351 square meters 351X9=3195 plants Answer: This piece of land can be planted corn 3159 plants.12: The number of students in a class of 100 people, queuing up, each row of 5 people, 4 people, 3 people are just more than one person, how many people in the class?5X4X3=60 people 60+1=61 people Answer: 61 people in the class.13: Wang Yue has a box of chocolate candy, 7 grains each time, 5 grains, 5 grains each time. Each time 7, 5, 3 of the number of the remaining 1, the box of chocolate candy at least how many? 7X5X3 = 105 105 + 1 = 106 Answer: The box of chocolate candy at least 106.14: Morning Glory neighborhood there is a section of 15 meters long, 1.2 meters wide rectangular canal to pave the square tiles. The designer has prepared a side length of 30 centimeters of square tiles, please calculate: how many of these square tiles are needed? If each square tile costs 3 yuan, then how many yuan is needed to pave this canal?15 meters = 150 decimeters1.2 meters = 12 decimeters30 centimeters = 3 decimeters150X12=1800 square decimeters3X3=9 square decimeters1800#9=200 200 200X3=600 yuanAnswer: 200 such tiles are needed, and 600 yuan is needed.15: There are two pieces of parallelograms of equal area. experimental field, a bottom edge length of 70 meters, 45 meters high, the other bottom edge length of 90 meters, how many meters high?70X45 = 3150 square meters 3150 # 90 = 35 meters Answer: the height of 35 meters.16: a number of steel tubes stacked into a pile, the lowest layer of 10, each on the level of 1 less than 1, the most upper layer put 5. How many of these tubes?10-5+1=6 layers (10+5)X6#2=15X6#2=90#2=45Answer: 45 tubes in this batch.