Math practice for 13 year olds - page 398 of 422
Number of problems found: 8427
- Blueberries
Marie earns 2.2 liters of blueberries for 1 hours, and Peter 2.5 liters for 1.5 hours. How long do they pick one liter together? - Arc
The length of the circle is 13, and the arc length of the circle is 5. What is the magnitude of the angle of this arc? - Two runners
Two runners ran simultaneously towards each other from locations distant 23.1 km. The average speed of the first runner was 1/7 higher than the average speed of the second runner. How long should each run a 23.1 km, if you know they meet after 58 minutes? - Machines
There are three machines in the workshop. The first treats 280 parts for 3.7 hours, the second treats 460 parts for 2.7 hours, and the third treats 550 parts for 3.6 hours. How long will it take to make 2440 parts if all three machines are worked simultan - Rectangles - sides
One side of the rectangle is 16 cm longer than a second. Shortening the longer side by 6 cm and extending the shorter by 9 cm increases the rectangle area by 250 cm². What are the dimensions of the original rectangle? - Two valves
Water fills the pool with two valves for 11 days. After 7 days, the workers stopped the first and second valve fill pool for 7 days. How many days did it take to fill the pool of each of the valves individually? - Posters
A column with posters in the form of a cylinder is 2 m high, and its diameter is 1.7 m. What is the area in which it is possible to stick posters? - Scale
The student drew the cylinder in scale 7:1. How many times is the volume of the cylinder smaller in reality? - Shooter
The shooter fired at a target from a distance 49 m. The individual concentric circle of targets has radius increments of 1 cm (25 points) by 1 point. The shot was shifted by 16' (angle degree minutes). How many points should he win his shot? - 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
From two points, A and B distant 29 km at the same time started two cars against each other at speeds 82 km/h and 72 km/h. How long do cars meet, and what distance passes each of them? - 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. - 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?
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