Math practice for 13 year olds - page 289 of 413

Number of problems found: 8260

Two workers
Two workers should fulfill specific tasks together for five days. If the first worker increased their performance twice and the second twice fell, it took them just four days. For how many days would he handle the entire task, the first worker himself?
Four Proportional Numbers
The first number is 50% of the second, the second number is 40% of the third, and the third number is 20% of the fourth. The sum is 396. What are the numbers?
The tower
The tower of the Dean's Church in Ústí nad Labem deviates from the original vertical axis by 220 cm. Its original height was 48 m. At what height is the highest point of this tower now? Enter the result to the nearest centimeter.
The pole
A 4 m wire brace supports a telegraph pole. It is attached at 3/4 of the pole's height, and its lower end is 2.5 m from the base of the pole. Calculate the height of the telegraph pole.
Circle diameter
The span of the arc is 247 cm, and the height of the arc is 21.5 cm. What is the diameter of the circle?
Cars Meeting Speed
At 10:00 AM, two cars drove against each other from places 240 km away. One was driving at an average speed of 70 km/h. What was the speed of the other when they met at 11:30?
Number Three Quarters Greater
Find the number whose three-quarters is five more than its one-third.
Parallelogram - sides
One side of a parallelogram is 8 cm long, which is two-sevenths of its perimeter. Calculate the length of the other side of the parallelogram.
Kinetic Energy Braking Force
Johnny is skating at a speed of 18 km/h. His kinetic energy is 0.5 kJ. Johnny weighs 40 kg. Calculate: 1. What work will the braking forces do before Johnny stops? 2. What is the braking force if Johnny stops after covering a distance of 14 m?
Two unknown numbers
One number is two less than a second number. Twice, the second number is 14 lower than five times the first. Find the two numbers.
The iron roller
The iron roller has a base circumference of 28 π cm. The worker drilled a hole through the top of the roller. After drilling, the given product had a 35% smaller volume than before. The hole's circumference in the base is equal to the height of the roller
Grain harvest
The farmer harvested 300 tons of grain, of which 18 tons were barley, wheat was 250% more than oats, and rye was 40% more than wheat. How many tons of individual grains did he harvest?
Hunt catch
Hunters shot the same number of pheasants as hares on the hunt. Together, they had catches of 408 feet. How many hares were there? (Suppose no animal was handicapped.)
Class Boys Girls Ratio
There are 21 students in the class, two times more boys than girls. How many boys and how many girls are in the class?
Seamstress
The seamstress cut the fabric into three parts. The first part was the eighth fabric, the second part was three-fifths of the fabric, and the third part had a length of 66 cm. Calculate the original length of the fabric.
Dress discount
The dress was reduced from CZK 840 to CZK 651. Calculate what percentage they have been discounted.
A truck
A truck left Znojmo at 7 am. He drove to Ostrava at an average of 56 km/h. 15 minutes later. A car went out of Ostrava at the same route from Znojmo at 64 km/h. What time did both vehicles pass and at what distance from Znojmo, if you know that the road d
Two-Digit Numbers Multiply Four
Write how many double-digit numbers there are, which, if we multiply by four, we get the result ending in two zeros.
Pool filling
How many hours will a block-shaped pool measuring 24 m, 12 m, and 1.8 m be filled if it flows through a 9 cm diameter pipe at a speed of 2.5 m/s?
Diamonds puzzle
The puzzle is composed of paper diamonds. One diamond (rhombus) has a diagonal 3.4 cm long and a corresponding height of 2.5 cm. How much paper in dm squared is needed for 60 diamonds?

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