Math practice for 13 year olds - page 307 of 428

Number of problems found: 8548

Water drainage
1000 l of water will drain in one outflow in 4 hours. How many hours will it take for 9000 l 3 drains to drain?
Acres
For two hours, 24 students harvested chestnuts on 36 acres. How many square meters are harvested by one student per hour?
Clock hands
How many times less would the hour hand per week describe if it was as long as the minute hand?
Ratio 11
Simplify this ratio 10: 1/4
Cuboid - volume and areas
The cuboid has a volume of 250 cm³, a surface of 250 cm², and one side 5 cm long. How do I calculate the remaining sides?
Apple weight
The box with apples weighs x kg. Empty box y kg. How many kilograms of apples are in twenty boxes?
Event comparison
Compare the odds of pairs of events. A) Slovakia will be the world champion in ice hockey 2 times in a row. B) You will write all the papers this year with at least a double. C) In two years, humans will be on Mars. D) Someone in your class will write all
Type of triangle
How do I find the triangle type if the angle ratio is 2:3:7?
Mirror
How far must Paul place a mirror to see the top of the tower 12 m high? The height of Paul's eyes above the horizontal plane is 160 cm, and Paul is from the tower distance of 20 m.
Cuboid walls
Calculate the cuboid volume if its different walls have an area of 195cm², 135cm², and 117cm².
Three-digit numbers
How many can you create three-digit numbers from the numbers 1,3,5,7 if we must not repeat the numbers?
Calculate the pool
Calculate how many square meters are needed to line the pool 6 meters long, 4 meters wide, and 1.5 meters deep. Add 10% to waste.
Tank diameter
The cylinder tank is 8 meters long and contains 40 cubic meters of petrol. What is its inside diameter?
Similarity coefficient
The triangles ABC and A'B'C' are similar to the similarity coefficient 2. The sizes of the angles of the triangle ABC are α = 35° and β = 48°. Find the magnitudes of all angles of triangle A'B'C'.
Average speed 4
Starting at home, Tony traveled uphill to the store for 45 minutes at 8 miles per hour. he then traveled back home on the same path at a speed of 24 miles per hour. What is his average speed for the entire trip?
Clocks
The length of the minute hand is 12 cm. What track in meters will its endpoint describe in a week?
Cuboid height
What is the cuboid's height if its base edges are 15 cm and 4 cm long and its volume is 420 cm cubic?
Friction coefficient
A body weighing 150 kg pulls with a force of 375N. What is the coefficient of friction?
Prism dimensions
We will double one block dimension and reduce the other by a third. How does its volume change?
The barrel
The barrel is 135 cm high. If we fill it to a height of 60 cm, it weighs 163 kg. If we fill it to a height of 80 cm, it weighs 213 kg. How many kilograms weigh a full and how many empty barrels?

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