Maths practice for 14 year olds - page 163 of 376

Number of problems found: 7501

Lookout tower
How high is the lookout tower? If each step was 3 cm lower, 60 more were on the lookout tower. If it were 3 cm higher again, it would be 40 less than it is now.
Even number creation
How many can even 2-digit numbers be created from the number 2,3,4,5 if it cannot repeat them?
Coffe cups
We have 4 cups with four different patterns. How many possible combinations can we create from 4 cups?
Alcohol from potatoes
In the distillery, 10 hl of alcohol can be made from 8 t of potatoes. The rectangular field with 600 m and 200 m dimensions had a yield of 20 t of potatoes per hectare. How many square meters of area are potatoes grown to obtain one liter of alcohol?
An observer
An observer standing west of the tower sees its top at an altitude angle of 45 degrees. After moving 50 meters to the south, he sees its top at an altitude angle of 30 degrees. How tall is the tower?
Coordinates
Determine the coordinates of the vertices and the area of the parallelogram, the two sides of which lie on the lines 8x + 3y + 1 = 0, 2x + y-1 = 0, and the diagonal on the line 3x + 2y + 3 = 0
Tournament
How many matches will be played in a football tournament in which there are two groups of 5 teams if one match is played in groups with each other and the group winners play a match for the tournament's overall winner?
Trip with compass
During the trip, Peter went 5 km straight north from the cottage, then 12 km west, and finally returned straight to the cottage. How many kilometers did Peter cover during the whole trip?
A bottle
A bottle full of cola weighs 1,320 g. If we drink three-tenths of it, it will weigh 1,008g. How much does an empty bottle weigh?
Building shadow length
How long a shadow casts a building 15 m high if the shadow of a meter rod is 90 cm? Sketch - similarity.
Cube paper calculation
Calculate how much cm² of paper needs to be bought to make a 60 mm cube if you need to add an extra 12% to the folds.
Diamond area calculation
The ABCD diamond has a circumference of 72 cm. The longer diagonal of the animal with the line segment AB angle is 30 °. Calculate the area of the ABCD diamond.
Finite arithmetic sequence
How many numbers should be inserted between the numbers 1 and 25 so that all numbers create a finite arithmetic sequence and that the sum of all members of this group is 117?
Penalty success rate
Martin, captain of the football team Lysice, converted 19 penalties, which means a success rate of 76%. How many penalties did Martin not convert?
Penalty success increase
Maroš, the captain of the football team Coyotes from Kojetín, converted 15 penalties out of 20, so he has a success rate of 75%. How many percentage points will his success rate increase if he converts the following 5 penalties without hesitation?
Per mille decimal
Write the per mille as a decimal number 2 ‰ 50 ‰ 2.5 ‰ 0.6 ‰
Per mille fraction
Write the per mille as a fraction Seven ‰ 25 ‰ 15 ‰ 10 ‰ 2.5 ‰ 1.7 ‰ 0.8 ‰ 2 ‰
Motorcycle engine
The motorcycle engine has a constant power of 1.2 kW for 0.5 hours. How much work does the engine do? Express work in kWh and Ws units.
Three examples per-mille
A. Calculate 1.5 ‰ from 4.5 liters of blood. Express the result in milliliters. B. Calculate three ‰ from € 50,000. C. The tray they brought breakfast to the landlord's bed is made of an alloy that contains 830 ‰ of silver. How much silver did they use on
Gas pipeline
Worker Molnár excavated the gas pipeline in 15 hours, worker Lakatoš in 12 hours, and worker Soukup in 10 hours. After how many hours of joint work will the excavation be completed?

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