Math practice for 13 year olds - page 231 of 424

Number of problems found: 8479

Six students
Two pupils painted the class in four hours. How long will it take for six pupils?
Mixture of nuts
We should prepare the mixture of nuts from almonds, peanuts, and nuts cashew ratio of 1:2:3 (respectively). The price of almonds is 150 CZK/kg, the price of peanuts is 140 CZK/kg, and the price of cashew nuts is 180 CZK/kg. The price of the mixture is det
Rectangle 12081
On a plan with a scale of 1:8000, the ski slope has 12 cm and 0.5 cm lengths. What is the actual piste area in ares?
The trapezium
The trapezium is formed by cutting the top of the right-angled isosceles triangle. The trapezium base is 10 cm, and the top is 5 cm. Find the area of the trapezium.
Blueberries
Five children collect 4 liters of blueberries in 1.5 hours. a) How many minutes do three children take 2 liters of blueberries? b) Eight children will take how many liters of blueberries in 3 hours?
Discounted 12041
The jacket initially cost 80 euros. Then it was discounted twice, always to 80% of the previous price. How much does it cost after the second discount?
Chocolate
Chocolate, which initially cost 1.5 euros, was increased by 40%. How many euros did it cost?
Positional energy
What velocity in km/h must a body weighing 60 kg have for its kinetic energy to be the same as its positional energy at the height of 50 m?
Floating of wood - Archimedes law
Wooden balsa block has a density of 200 kg/m³ and a volume of 0.02 m³ floating in alcohol. Alcohol density is 789 kg/m³. What will be the volume of the floating part of a balsa block?
Cheops pyramid
The Pyramid of Cheops is a pyramid with a square base with a side of 233 m and a height of 146.6 m. It is made from limestone with a density of 2.7 g/cm³. Calculate the amount of stone in tons. How many trains with 30 twenty-ton wagons carry the stone?
Five numbers in ratio
Five integers are in the ratio 1:2:3:4:5. Their arithmetic mean is 12. Determine the smallest of these numbers.
AM of three numbers
The number 2010 can be written as the sum of 3 consecutive natural numbers. Determine the arithmetic mean of these numbers.
What 11781
What is greater: 2/5 of 10, or 20% of 4000?
Calculate 11771
The interior angles of the triangle are 108 degrees 45 minutes and 51 degrees 19 minutes. Calculate the outside angle at the third vertex.
Mathematicians 11761
The top five mathematicians in the class took on the teacher's help in calculating the paper's average grade. They dictated the following results: Mischa: "I came up with 3.30. " Dasha: "That's weird because it worked out precisely at 3.45. " Jana: "You p
Alcohol
6l 48% alcohol, how much must we add 52% alcohol to give 50% alcohol?
Distance 11711
The observer sits in a room 2 m from a 50 cm wide window. A road runs parallel at a distance of 500 m. What is the cyclist's average speed on this road when the observer sees him at 15 seconds?
Cost reduction
Fourteen pieces of goods cost just as much as 21 pieces before the discount. The price of one piece after the discount is CZK 1.50 lower than before the price reduction. How much was one piece before the discount?
Agricultural 11691
The tractor leaves the field and heads towards an agricultural cooperative 14 km away at an average speed of 20 km/h. Twenty minutes later, an agronomist followed him from the same field on a motorcycle at an average speed of 45 km/h. Will he catch up wit
Cylinder and its circumference
The height of a cylinder is four times its circumference, c. What is the volume of the cylinder in terms of its circumference c?

Do you have unsolved math question and you need help? Ask a question, and we will try to solve it. We solve math question.