Math practice for 13 year olds - page 61 of 414
Number of problems found: 8279
- Republican calendar conversion
In the republican calendar (used in France from 1793 to 1805), one full day was divided into 10 hours; each hour had 100 minutes, and each minute had 100 seconds. What time would the clock show at that time when today's clock reads 15:36? - Dimensions of an aquarium
The large aquarium is shaped like a cuboid and has dimensions in the ratio 5: 7: 4. The sum of the lengths of all edges is 96 dm. How many liters of water will be in the aquarium if it is filled to four-fifths? - Skiing and sledding
Behind the pond, the cat Miki is skiing and Bobo is sledding down a 300-meter-long slope. Careful Bobo can go down the slope in one minute. How many km/h faster does Miki go down the hill than Bobo if he is down 20 seconds earlier? - Banknote cash register
Cashier Samuel had a total of 20 banknotes in the cash register with a total value of 850 euros. They were only €50 and €20 notes. How many of each bill did he have? - Cylinder volume ratio
Calculate the cylinder's volume if you know that the ratio of the cylinder's height to the base's radius is 3:2 and the height is 15 dm. - Katy 7
Katy ordered a cylinder-shaped cake with a volume of 15.7 litres. It consists of two layers. The volume of the upper layer is 4 times smaller than the volume of the lower layer. The height of both layers is the same and equals the radius of the upper laye - Pokemon card distribution
Jenda, Milo, and Thomas have a total of 203 Pokemon cards. Jenda has twice as many cards as Thomas, and Milo has a quarter of Jendo's number of cards. a) How many cards does Jenda have? b) How many fewer cards do Milo have than Jenda and Thomas? - Ondra book pages
Andrew was reading a book. On the first day, he read one-tenth. On the second day, he read half of the remainder. On the third day, he read 20% of the new remainder, and on the fourth day, he read the remaining 72 pages. How many pages did the book have? - Rubber drawing probability
The grandfather bought 10 rubbers for 10 grandchildren. In the bag were 3 blue, 2 green and the rest red. Hansel would like blue gum. What is the probability that Janek will draw a blue rubber if 2 cousins have already drawn it before him and drawn blue a - Garden trapezoid mesh
The garden is a rectangular trapezoid a=50 m, c=30 m, d=15 m. If we add an 8% loss to the calculated length, how many meters of mesh do we need to fence it? - Courtyard oak bricks
The castle courtyard, with an area of 100 m², is paved with oak cubes with an edge of 8 cm. Approximately 164 bricks were used to pave m². One dm³ of oak wood weighs 0.8 kg. Calculate the weight of all the bricks used to pave the courtyard. - Jana notebook purchase
Jane bought 36 notebooks, three times as many with lines as with squares notebooks. Calculate how many lined notebooks she purchased. - Airship
An airship is at a height x above the ground. Pavel watches it from point A at an elevation angle of 18°26'. At the same time, Peter sees it from a small plane that is currently flying over Pavel at an altitude of 150 m. Peter sees the airship at an eleva - Spider fly legs
There are spiders and flies on the window. They have a total of 38 legs. How many spiders and flies are there if a spider has 8 legs and a fly has 6? Just give one solution. - Class weight average
There were 31 students in the class, and the arithmetic average weight was 43 kg. Calculate the average weight in the class if a student weighing 91 kg has been added to the class. - Salt solution
The 50% salt solution must be diluted with distilled water to make 20 liters of 35% solution. How many liters of original solution and how many liters of water do we need? - Plot plan price
On the 1:75 scale plan, the building plot is a rectangle with 60 cm and 50 cm dimensions. If 1 m² of land costs 80 euros, what is the price of the land? - Jane bought
Jane bought several identical lined notebooks, several identical squared notebooks, and several identical compasses at a stationery store. Two lined notebooks and two squared notebooks cost a total of 180 crowns. Two squared notebooks cost the same as thr - The ladder and wall
A 6.5-meter-long ladder rests against a vertical wall. Its lower end rests on the ground 1.6 meters from the wall. Determine how high the top of the ladder reaches and at what angle it rests against the wall. - Kite deltoid angles
A paper kite is shaped like a deltoid ABCD, with two shorter sides 30 cm long, two longer sides 51 cm long, and a shorter diagonal 48 cm long. Determine the sizes of the internal angles of the given deltoid.
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