Maths practice for 14 year olds - page 128 of 376

Number of problems found: 7502

Swimming student
There are 200 pupils in the class, 40% of whom cannot swim. How many students can swim?
Frequency distribution
The following frequency distribution gives the time spent for a fill-up at a gas station. Assume that each value in a class is equal to the midpoint of the class. Estimate the mean fill-up time for the given data. Please round your answer to the neares
Jewelry factory
In a jewelry factory, three assemblers make beaded necklaces. Marcus can make 22 necklaces per hour all day long. Anita can make 25 necklaces for her first three hours of the day and then slow down to 16 necklaces for the rest of the day. Yara can make 2
The diamond
The diamond has an area S = 120 cm², and the ratio of the length of its diagonals is e: f = 5:12. Find the lengths of the side and the height of this diamond.
Workshops
The plant has three workshops. In the first workshop, produce five products/hour. In the second 8 products/hour, and in the third, seven products/hour. In the first workshop, they produced 240 products. In the second 400 and the third 350 products. Find t
Czech coins
John has 540 CZK, but he only has 10 and 20 CZK coins. We know that he has 10 CZK coins, seven times more than 20 CZK coins. How many 10CZK coins and how many 20CZK coins did he save?
Car sign
How many cars can we mark with signs that only use the letters A, B, and the number 1,2? The tag contains two letters and three digits.
Two cables
On a flat plain, two columns are erected vertically upwards. One is 7 m high, and the other 4 m. Cables are stretched between the top of one column and the foot of the other column. At what height will the cables cross? Assume that the cables do not sag.
Pyramid stone weight
The largest Egyptian pyramid has the shape of a regular four-sided pyramid with a base edge of approximately 227 meters and a height of about 140 meters. How many tons of stone did the workers transport to build it? One cube of stone weighs 2500 kg and ne
Plot dimension increase
The surface area of the rectangular plot needs to be increased by 33.7 percent. One dimension was extended by 2.9 percent. By what percentage should the second dimension be increased? Round the result to two decimal places.
Fireplace power consumption
A current of 20 A passes through the heating spiral of the electric fireplace with a resistance of 10Ω for 2.5 hours. Determine the power input of the fireplace and the consumed electrical energy
Bulb voltage current
The bulb's resistance at a power input of 40 W is 10 Ω. To what voltage source is it connected? How much current is flowing through it?
Bulb resistance
Determine the resistance of a bulb whose wattage at a source voltage of 220 V is 15 W.
A number 4
A number is made up of two digits. The sum of the digits is 11. if the digits are interchanged, the original number increases by 9. Find the original number
Ramon
Ramon earns 1,810 each month and pays a 53.20 bill on electricity. To the nearest tenth of a percent, what percent of Ramon's earnings are spent on electricity each month?
The roof
The house's roof has the shape of a regular quadrilateral pyramid 5 m high and the edge of the base 7 m. How many tiles with an area of 540 cm² are needed?
Cathedral roof sphere
Cathedral height is 110 m, sphere weight 6000 kg, dome diameter 43 m, crane arm length 25 m a) what was the diameter of this sphere? b) how much mechanical work had to be done to lift it to the designated place?
Transmission of electricity
The electric field performs work 1610 J in the transmission of electric charge of 7 Coulombs between the heating coil terminals. Calculate the voltage between the terminals.
Milk cream
How many percent of whipped cream do we make if we mix 41 liters of 38.8% whipped cream and 9 liters of 3.8% milk? (Percent means a percentage of milk fat).
Exam average
Jane has to pass ten exams in a year. So far, she has made six and has an average of 2.5. What average must she reach from the remaining tests for her overall average for the year to be 2?

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