Maths practice for 14 year olds - page 306 of 368

Number of problems found: 7348

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?
Difference 3101
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.
Water temperatures
To 25 liters of water at 50 °C, we add 15 liters of water at a different temperature. How many °C should the water be colder than 50 °C so that 40 liters of the water obtained has a temperature of 42.5 °C?
Concentration 3098
Calculate the concentration of the solution prepared from 6 kg of 95% sulfuric acid solution and 24 kilograms of 10% sulfuric acid solution.
Concentration 3097
How many liters of 60% and 80% formic acid do we have to mix to get 80 liters of this acid with a concentration of 65%?
Candy
The price for 1kg of more expensive candy is 125 CZK. The price for 1kg of cheaper candy is 100 CZK. We make two different blends of candy. And now. The second blend contains 2 kilograms of more expensive candy and several kg of cheaper candy. The price p
Kilograms 3094
1.5 kg of a 20% NaCl solution should be diluted to a 10% solution with water. How much water will we need, and how many kilograms of diluted solution will we get?
Alcohol
How many cubic centimeters of 96% alcohol is needed to obtain 0.75 liters of 40% alcohol?
Solution 3092
How many liters of 80% alcohol need to be mixed with 4 liters of 40% alcohol to get 70% alcohol? How many liters of 70% solution do we get?
Numbers 3090
The sum of the two numbers is 52.5. The first number makes up 75% of the second number. Specify both numbers.
Solution
What amount of 80% solution and water is needed to mix to obtain two liters of 60% solution of this mixture?
Circumference 3088
In the parallelogram ABCD, the side AB is three times longer than the side BC. The circumference of the parallelogram is 20 cm. Find the lengths of the sides of the parallelogram.
Two-digit 3085
How many two-digit numbers can you create from the digits 7,0,1 and 5 if the numerals can be repeated?
Gp - 80
One of the first four members of a geometric progression is 80. Find it if we know that the fourth member is nine times greater than the second.
Contestants
In the competition, it was possible to get 0-5 points. Five of the 15 best contestants have earned 5 points or 4 points (which have won 10 contestants). The number of contestants who scored 3 points was the same as those who did not get any points. Calcul
Digging
A pit is dug in the shape of a cuboid with dimensions 10mX8mX3m. The earth taken out is spread evenly on a rectangular plot of land with dimensions of 40m X 30m. What is the increase in the level of the plot?
Fog
The car started in fog at a speed of 30 km/h. After a 12-minute drive, the fog dissipated, and the driver drove the next 12-minute distance, 17 km. The driving conditions deteriorated during the last 17 km, and the driver drove at 51 km/h. a) Calculate th
Probability 3065
Natural numbers 4,5,7,11,12 are given. Calculate the probability of the event that the sum of three randomly selected numbers is less than 22.
AP 6
Calculate the first five items of an arithmetic sequence if it is given: a₂ – a₃ + a₅ = 20 a₁ + a₆ = 38

Do you have homework that you need help solving? Ask a question, and we will try to solve it. Solving math problems.