Math practice for 13 year olds - page 403 of 426
Number of problems found: 8519
- Mushrooms
Fresh mushrooms contain 94% water and dried 9%. How many kilograms of fresh mushrooms are needed to collect to get 10 kg dried? - Against each other
Two cars start simultaneously from points A and B, which are 29 km apart, and travel toward each other at speeds of 82 km/h and 72 km/h. How long until they meet, and what distance does each car travel? - Motor physics
A car is traveling at 104 km/h on the highway. The pulling power of the motor is 10 kN. Find the engine power in kW. - Ratio
Unfold number 3690 in the ratio 15:11:4. - Pedestrian
A pedestrian came started at 7h in the morning with a speed of 3.2 km/h. At half-past eleven, the cyclist started at 30 km/h the same way. How long does the cyclist take to catch up with the pedestrian? - Parquet floor
Three workers laid the parquet floor for 2.301 hour. The first would do this work alone 7 hours, the second in 6 hours. For how many hours would this work for the third worker if he worked alone? - Inflow - outflow
The tank will fill by inflow for 56 minutes and empties by outflow for 77 minutes. How long does it take to fill the tank if it is open to inflow and outflow? - Painters
The first painter painted the fence himself for 10 hours, the second painter 2.7 hours sooner than the first, and the third painter slowest up to 21 hours. How long took them to paint the fence if they worked together? - OPT
What is the perimeter of a right triangle with the legs 11 cm and 24 cm long? - Elevation
What must be an observer's elevation so that he may see an object on the Earth 866 km away? Assume the Earth to be a smooth sphere with a radius 6378.1 km. - Horizon
The top of a lighthouse is 18 m above the sea. How far away is an object just "on the horizon"? [Assume the Earth is a sphere of radius 6378.1 km.] - Air
The room is 35.6 m long, 19.6 dm wide, and 591 cm high. How many people can simultaneously be in this room if, for hygiene reasons, is calculated 5000 dm³ of air per person? - Roller
Roller has a diameter of 0.89 m and a width of 225 cm. How many m² of road level when he turns 30-times? - Metallurgical enterprise
Metallurgical company daily produces 501 tons of cast iron. How many tons of coke does it burn to melt cast iron when 14 tons of cast consumes 10 tons of coke? - Square
If we increase one side of the square by its one-half, then the square perimeter increases by 4 cm. What is the side of the square? - Accidents
The count of accidents in 1991 caused 8444 women, which is 9%. How many men caused the accidents? - Map - climb
On the map of the High Tatras, on a scale of 1:11000, are cable car stations in the Tatranska Lomnica and the Skalnate Pleso with a distance of 354.6 mm. The altitude of these stations is 949 m and 1760 m. What is the average angle of climb on this cable - Bottle
Bottle with wine costs 42 USD. Wine is 11 USD more expensive than the empty bottle. How much is the bottle itself? - Circumferential angle
Vertices of the triangle ΔABC lay on the circle and are divided into arcs in the ratio 10:8:7. Determine the size of the angles of the triangle ΔABC. - Center of the cube
The Center of the cube has a distance 40 cm from each vertex. Calculate the volume V and surface area S of the cube.
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