Math practice for 13 year olds - page 311 of 423
Number of problems found: 8459
- Right triangle trigonometrics
Calculate the size of the remaining sides and angles of a right triangle ABC if it is given: b = 10 cm; c = 20 cm; angle alpha = 60°, and the angle beta = 30° (use the Pythagorean theorem and functions sine, cosine, tangent, cotangent)
- Forces on earth directions
A force of 60 N [North] and 80 N [East] is exerted on an object weight of 10 kg. What is the acceleration of the object?
- Volume increase
How much percent will increase in the pool 50 m, width 15m if the level rises from 1m to 150cm?
- Hydrostatic force
What is the hydrostatic force applied to an area of 30 cm² in the water at a depth of 20 m? (Water density is 1000 kg/m3)
- Sales of products
For 80 pieces of two quality products, the total sales are 175 Eur. Suppose the first quality product was sold for n EUR per piece (n natural number) and the second quality product after 2 EUR per piece. How many pieces of the first quality were sold?
- Sphere radius
The surface of the sphere is 60 cm square. Calculate its radius; result round to tenth of cm.
- Championships 4886
The pool had to be filled before the World Championships. The first pump would fill in 12 hours, the second in 15 hours, and if all three pumps were started simultaneously, they would fill the pool in 4 hours. How long would the pool be filled with only t
- Two-digit 4883
Dad had 33 bills. One hundred crowns, two hundred and five hundred. A two-digit number gave the number of each species. How many did he have if he had a total of 9100 CZK?
- Three-digit 4882
There were 301 postage stamps in the desk drawer. They were stamps for 2, 3, and 5 crowns. The number of each species can be written as a three-digit number. The total price of all stamps is CZK 1,003. How many stamps were there?
- Individual 4881
There are 32 rooms in the hostel. Some have double beds, others have four beds and the rest have 7 beds. There are a total of 139 beds in the hostel. How many are there if a two-digit number gives the numbers of individual species?
- Five-crowns 4879
Eva had seven coins. Crowns, two-crowns, and five-crowns. At least two of each. How many did she have if she could buy three packs of gum for six crowns?
- Weighs 4877
A + B weighs 75 kg, B + C weighs 83 kg, C + D weighs 92 kg. How much does A + D weigh?
- Disc
The circumference of the disk is 78.5 cm. What is the circumference of the circular arc of 32° on the disc?
- Sides of the triangle
The sides of the triangle ABC have a length of 4 cm, 5 cm, and 7 cm. Construct triangle A'B'C', similar to triangle ABC, which has a circumference of 12 cm.
- Map scale
On a 1:1000 scale map is a rectangular land of 4.2 cm and 5.8 cm. What is the area of this land in square meters?
- Distance 4869
Two places have a distance of 4 cm on a map with a scale of 1:75 000. What is their distance on a 1:50,000 scale map?
- Recommended 4866
The two Honzos had buns. The first 6, the second 4. They split with their grandmother so that they all had the same amount. Grandma gave them 5 apples. The first wanted 3, the second wanted 2. The second wanted, on the contrary, Grandma recommended dividi
- Calculate 4865
Calculate the length of the line segment AB, given A [8; -6] and B [4; 2]
- Inscription 4864
From the beginning of the year, students in 4th grade wrote a chronicle. She had everything they had together, and they cared a lot about her. But one day, the chronicle was lost. Five students were left to search for everything on Monday after the class.
- Socks
One pair of socks is worth CZK 27. A set of three pairs of these socks is sold with a 10% discount. How much will we pay for two offered sets of socks?
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