Maths practice for 14 year olds - page 161 of 370

Number of problems found: 7386

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?
Similarity 26441
How long a shadow casts a building 15 m high if the shadow of a meter rod is 90 cm? Sketch - similarity.
Calculate 26433
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.
Selected 26381
Seven people need to be selected from the sports club, where 11 men and nine women. How many ways can we do this if seven women are on the team?
Circumference 26361
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?
Penalties 26341
Martin, captain of the football team Lysice, converted 19 penalties, which means a success rate of 76%. How many penalties did Martin not convert?
Percentage 26321
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?
Decimal 26301
Write the per mille as a decimal number 2 ‰ 50 ‰ 2.5 ‰ 0.6 ‰
Fraction 26291
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?
Determine 26191
The rectangle has side lengths of a = 40 cm and b = 10 cm. We reduce side a's length by 30% and side b by 10%. Determine how much less the area of the rectangle has decreased in percentages.
Motorcyclist and a car
The passenger car left at 7:00 and was heading east at a speed of 60 km/h. A motorcyclist left the same place and headed north at 40 km/h. What will be their air distance at ten o'clock?
Horizontal 26131
What height difference does the 2.5 km long ski lift overcome when the horizontal distance of the entry and exit station is 1200 meters?

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