Reason + expression of a variable from the formula - math problems

Number of problems found: 68

• A cylinder
A cylinder 108 cm high has a circumference of 24 cm. A string makes exactly 6 complete turns around the cylinder while its two ends touch the top and bottom. (forming a spiral around the cylinder). How long is the string in cm?
• Soaps
Each box has the same number of soaps. A quarter of all boxes contain only white soaps, and in each of the remaining 120 boxes there are always half the white soaps and half the green. White soaps total 1200. (a) the number of all soap boxes; (b) the smal
• Equilateral triangle
A square is inscribed into an equilateral triangle with a side of 10 cm. Calculate the length of the square side.
• The coil
How many ropes (the diameter 8 mm) fit on the coil (threads are wrapped close together) The coil has dimension: the inner diameter 400mm, the outside diameter 800mm and the length of the coil is 470mm
• ABCD square
In the ABCD square, the X point lies on the diagonal AC. The length of the XC is three times the length of the AX segment. Point S is the center of the AB side. The length of the AB side is 1 cm. What is the length of the XS segment?
• Digit sum
The digit sum of the two-digit number is nine. When we turn figures and multiply by the original two-digit number, we get the number 2430. What is the original two-digit number?
• Average age
The average age of all people at the celebration was equal to the number of people present. After the departure of one person who was 29 years old, average age was again equal to the number present. How many people were originally to celebrate?
• VAT on books
The cost of a book in the store is 12.5 euros. How much euros is the VAT of this book? VAT is 10%.
• ICE train
German runways test a new ICE train between Munich and Berlin. The train runs to Berlin at a slow speed of 100 km/h. Back from Berlin goes faster. How quickly did the train have to go on a return trip so that the total average train speed for both journey
• Isosceles triangle
The perimeter of an isosceles triangle is 112 cm. The length of the arm to the length of the base is at ratio 5:6. Find the triangle area.
• Direct route
From two different places A and B connected by a direct route, Adam (from city A) and Bohus (from city B) started at a constant speed. As Adam continued to go from A to B, Bohus turned around at the time of their meeting, and at the same speed, he returne
• Wine
A bottle of wine costs 21 euros, and wine is 20 times more expensive than a bottle. How much does a bottle cost?
• Oil tank and pipes
The underground oil tank can be filled by two oil pipelines. The first is filled in 72 hours and the second in 48 hours. How many hours from the moment when first pipeline began to fill the oil is it necessary to start filling it with the second to fill i
• Trucks
Three lorries droved bricks. One drove n bricks at once, the second m fewer bricks than the first and third 300 bricks more the first lorry. The first lorry went 4 times a day, the largest went 3 times a day, and the smallest lorry 5 times a day. How many
• Trapezoid thirds
The ABCD trapezoid with the parallel sides of the AB and the CD and the E point of the AB side. The segment DE divides the trapezoid into two parts with the same area. Find the length of the AE line segment.
• Two trucks
Two trucks left cities A and B against each other and met after an hour. The first car came to B 27 minutes later than the second car to A. Calculate the car speed if the distance between cities A, B is 90 km.
• Rectangle diagonals
It is given a rectangle with an area of 24 cm2 a circumference of 20 cm. The length of one side is 2 cm larger than the length of the second side. Calculate the length of the diagonal. Length and width are yet expressed in natural numbers.
• MO-Z5-3-66 tiles
The picture shows square tiles with a side of 10 dm, composed of four identical small rectangles and squares. The circumference of a small square is five times smaller than the circumference of the entire tile. Determine the dimensions of the rectangle.
• Apples 5
In six crates are 45 kg of apples. In five crates were the same amount and in one crate was 3 kg of apples more. How many kg of apples were in each crate?
• Four integers
Fnd four consecutive integers so that the product of the first two is 70 times smaller than the product of the next two.

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Reason - math problems. Expression of a variable from the formula - math problems.