Examples for 8th grade - page 22
In the workshop are three machines. The first is treated 350 parts for 4.3 hours, the second is treated 490 parts for 4.6 hours and the third is treated 360 parts for 3.7 hours. How long will take to make 3080 parts if worked all three machines at the.
Perpendicular pole high 6 m tall broke and its toe fell 2.8 m from the bottom of the pole. At what height above the ground pole broke?
- Isosceles - isosceles
It is given a triangle ABC with sides /AB/ = 3 cm /BC/ = 10 cm, and the angle ABC = 120°. Draw all points X such that true that BCX triangle is an isosceles and triangle ABX is isosceles with the base AB.
- Barrel 3
Barrel with water has a weight 118 kg. When we get off 75% of water it has a weight 35 kg. How many kg has empty barrel?
- Percentage reduction
Reducing the unknown number by 36% get number 937.3 Determine unknown number.
Calculate distance between two points Z[7; -9] and U[-10; -8].
If water flows into the pool by two inlets, fill the whole for 9 hours. First inlet filled pool 8 hour longer than second. How long pool is filled with two inlets separately?
- Bicycle wheel
Bicycle wheel has a diameter of 60 cm. Approximately how many times the wheel rotates at 3.7 km long trip?
Grandmother baked cakes. Half of its was poppy, quarter with plum jam and 16 cheesecakes. How many cakes she baked in total?
On the trip drank 3/10 of pupils tea, 2/5 cola, 1/4 mineral water and remaining 3 juice. How many students were on the trip?
- Water container
Container with water weighs 1.48 kg. When we cast 75% of water container of water weight 0.73 kg. How heavy is an empty container?
Janitor tosses 26 cm layer of snow on the school grounds for 90 minutes. How many friends would have to call for help if snow needs to have bowled for 15 minutes. We assume that at the same time bow all the same amount of snow.
Find the cuboid that has the same surface area as the volume.
Alena read a book at speed 15 pages per day. If she read twice as fast she should read a book four days earlier. How many pages have a book?
- Angles ratio
In a triangle ABC true relationship c is less than b and b is less than a. Internal angles of the triangle are in the ratio 5:4:9. The size of the internal angle beta is:
- Three friends
The three friends spent 600 KC in a teahouse. Thomas paid twice as much as Paul. Paul a half less than Zdeněk. How many each paid?
- Chicken and rabbits (classic)
Grandmother breeding chickens and rabbits. It found that the yard has 22 heads and 66 legs. How many chickens and rabbits breeding in the yard?
- Midpoint of segment
Point A has coordinates [15; 1] and the midpoint of the segment AB is the point [-20; 13]. What are the coordinates of point B?
How many different ways can sit 5 boys and 5 girls in line, if girls want to sit on the edge?
From the observatory 15 m high and 39 m from the river bank, river width appears in the visual angle φ = 22°. Calculate width of the river.