Maths practice for 14 year olds - page 309 of 375

Number of problems found: 7493

Prism - box
The prism's base is a rectangle with a side of 7.5 cm and 12.5 cm diagonal. The volume of the prism is V = 0.9 dm³. Calculate the surface of the prism.
Body diagonal
Find the cube surface if its body diagonal has a size of 6 cm.
Oil cans
Workers rolled the oil into 115 two-liter and three-liter cans from a full three-hectolitre barrel. How many cans were there?
Cylinder
A 1-meter diameter cylinder is 1413 liters of water, which is 60% of the cylinder. Calculate the cylinder height in meters, do not write the units. Please the resulting value round and write it as an integer.
Triangle perimeter
The right triangle has squares in the ratio of 5:12, and the circumscribed circle diameter is 26 cm. Determine its perimeter.
Gardens
I have a garden in the shape of a square with a side length of 0.02 kilometers. The neighbor has a large garden, and we share one side of the garden. I bought from a neighbor's garden, and my garden area increased to 5 ares. I. By how many acres I purchas
Siblings
Three siblings had saved up a total of 1,274 CZK. Peter had saved up to 15% more than Jirka and Hanka, 10% less than Peter. How much money did they save for each one of them?
Painting
The room is 50 meters long, wide 60 dm, and 300 cm high. Calculate how much it will cost to paint if the area of windows and doors is 15% of the total area. One square meter costs 50 cents.
Costume
Denisa is preparing for a goldsmith's costume carnival. During the preparations, she thought she would let her hair wipe instead - she would apply a 5 μm thick layer of gold to each hair. How much gold would Denisa need? Assume that all hundred thousand D
Concentration
How many grams of 65% and 50% acid are to be mixed to give 240 g of acid with a concentration of 60%?
Hydrochloric acid
Determine the concentration of which must have a solution of hydrochloric acid that mixes 10 l of the solution with 8 liters of 26% solution to get the solution with a concentration of 50%.
Acid solution
By adding 250 grams of a 96% sulfuric acid solution to its 3% solution, we changed its initial concentration to 25%. How many grams of 3% of the acid were used for dilution?
Product of three
The product of 3 numbers is 42. The first is 1.5 times larger than the second number, and the third is 3.5 times larger than the second number. What numbers are these?
Water mixing
Find how many liters of water at 80 °C and 20 °C need to mix to get 30 liters at 60 °C.
Tree storm
In the orchard, there were 46 more apple trees than pears. The storm upset a quarter of apple trees and seven pears; however, there were still 80 trees left. How many were apple trees, and how many pears were in the garden?
Apple baskets
How many apples are in the fifth and eighth baskets if there are five apples in the first and 11 more apples in the next than in the previous one?
Water mixing - tub
The tank has water with a volume of 300 liters and a temperature of 10 °C. Add water at a temperature of 90 °C until a temperature of 30 °C is reached. How many liters of warmer water do I need to add?
Concrete block
Determine the volume of the concrete block whose one edge of the base is 3 meters long, the body diagonal is 13 meters, and the height is 12 meters.
Distilled water
Seawater contains 5% salt. How much distilled water should be poured into 40 kg of seawater so that the salt content is 2%? How many kilograms of 2% of seawater do we get?
Number difference
The difference between the two numbers is 4/3. If you know that the first number is 50% larger than the second number, specify both numbers.

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