Math practice for 13 year olds - page 250 of 413
Number of problems found: 8260
- Bicyclist Meeting Walker
At 8:00, Peter set out on a hike at 5 km/h. At 9:12, Michael followed him on a bike at a speed of 20 km/h. At what time did Michael catch up with Peter, and how many kilometers did he cover? - Polder filling
The polder has two tributaries. A larger inflow will fill an empty polder in 12 hours. The polder is already a quarter full. If we open both tributaries, the polder will be filled in 6 hours. How long would it take for a smaller inflow to fill an empty po - Two number sum
The sum of the two numbers is 46. It holds that two times the first is one greater than three-fifths of the second. What are the numbers? - Reminder and quotient
Numbers A = 135 and B = 315 are given. Find the smallest natural number R greater than one so that the proportions R:A, R:B are with the remainder 1. - Car crash
After a traffic accident, police measured 1.16 permille of alcohol in the driver's blood. About 5 kg of blood circulates in the human body. What amount of alcohol did the driver have in the blood? - Circular arc length
The length of the circular arc at the corresponding angle of 120 ° is 8 cm. What is the size of the whole circle? What is its radius? - Workshops
The first workshop will complete the robot itself in 15 days, and the second workshop in 10 days. They started together, but only the second workshop worked after three days. Thus, the work will take 15 days. - Two pipes
How long will it take to fill the pool using both supply pipes if the first pipe alone fills it in 4 hours and the second pipe takes 9 hours longer than both pipes running together? - Oven carrying weight
The inner radius of the oven is r1 = 15cm, the outer radius is r2 = 20cm, and the length is 227cm. Can one person take it if its material density is 2.8 g / cm cubic? - Inquality
Solve inequality: 3x + 6 > 14 - Container diameter calculation
What is the diameter of a cylindrical container if half a liter of water reaches a height of 12 cm? - Pool pump filling
At the swimming pool, they use three pumps with the same output to fill the pool and fill the pool in 6 hours. How long does it take for the pool to fill nine pumps? - Divide 5
Divide number 288 by the following ratio of 3:4:5. - Simple equation 6
Solve the equation with one variable: X/2+X/3+X/4=X+4 - At a party
At a party 12 guests left their shoes in the hallway. In total there were 6 pairs of men's shoes, 6 pairs of women's shoes, 6 pairs of brown shoes, 6 pairs of black shoes. After the party it was found that some of the shoes had disappeared. 5 men's and 5 - Bicycle wheel turns The pedal wheel on a bicycle has 28 teeth. The gear wheel on the rear wheel has 8 teeth. How many times does the rear wheel turn if we step on both feet 112 times? How many meters can we travel with it at least, and how much more if the rear wheel has a d
- Gas Air Weight Ratio
One m³ of air weighs 13/10 kg, and the same volume of natural gas weighs 4/5 kg. How many times lighter is the gas than air? - One trapezium
One trapezium has AB=24M, BC=36M, CD=80M, DA=80M long sides. Find the area. - Prime inequality solutions How many prime numbers are the inequality solutions: x / 3> x - 8?
- Iron density Calculate the weight of a 2 m long rail pipe with an internal diameter of 10 cm and a wall thickness of 3 mm. The iron density is p = 7.8 g/cm³.
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