Math practice for 13 year olds - page 254 of 424
Number of problems found: 8480
- Pupils
There are 350 girls in the school, and the other 30% of the total number of pupils are boys. How many pupils does the school have? - Difference 7641
To get their sum, what number do you have to multiply the difference between 3 1/2 and 2 3/4? - Chickens and hares
There were chickens and hares in the yard. Together they had 22 heads and 54 legs. How many hens were there in the yard? - Opposite 7634
The first worker digs a canal in 3 hours. The other will dig the trench in 4 hours. They will work 1 hour opposite each other and then together. How long will it take them? - Shelves 7633
Juraj had music CDs and DVDs stored on the shelves. There are a total of 64. How many DVDs are on the shelf if there are seven times less than a CD? - Equation - inverse
Solve for x: 7: x = 14:1000 - Kilometers 7631
At 8:00, Peter set out on a hike at 5 km/h. At 9:12, Michal followed him on a bike at a speed of 20 km/h. At what time did Michal Petra run, and how many kilometers did he cover? - Tributaries 7630
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 - Three-fifths 7629 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? - Corresponding 7621
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 the pool be filled with a double supply pipe if it takes the pool to fill the first pipe by 4 hours long and the second pipe 9 hours longer than both pipes open simultaneously? - Material 7608
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 - Cylindrical 7603
What is the diameter of a cylindrical container if half a liter of water reaches a height of 12 cm? - Swimming 7602
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. - Two airports
Two airports are 2690 km away. From the first airport, the airplane flies at a speed of 600 km/h, and from a second airplane at a speed of 780 km/h. When will they meet if they fly at 10:00? How far from the first airport?
Do you have homework that you need help solving? Ask a question, and we will try to solve it. Solving math problems.
