Examples for 8th grade - page 22
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?
- Isosceles trapezoid v3
In an isosceles trapezoid ABCD is the size of the angle β = 71° Determine size of angles α, γ and δ.
- Rotary cylinder
The rotating cylinder has a surface area 69.08 cm2. The area of the shell is 62.8 cm 2. What is the diameter of the cylinder?
- Feed for horses
In the kennel have feed for two horses for 21 days. The station brought an additional 5 horses. How many days will last the feed for all the horses if they have the same daily ration?
How many different ways can initiate a game of chess (first pass)?
- Hockey players
After we cycle five hockey players sit down. What is the probability that the two best scorers of this crew will sit next to each other?
Perimeter of regular hexagon is 41. Calculate its circumradius (radius of circumscribed circle).
- Price reduction
Price of camera is 800 USD on sale its price reduced to 423 USD. Calculate the percentage reduction in the price of the camera.
The rod are 1.7 m long hanging weights 2 kg and 12 kg on ends. Where are centre of rod (distance from weight 2 kg) to be in balance?
Large backpack cost CZK 1352, little is 35% cheaper. How much we paid for 5 large and 2 small backpacks?
- Cuboid aquarium
Cuboid 25 times 30 cm. How long is third side if cuboid contains 30 liters of water?
Less than 20 children is played various games on the yard. They can create a pairs, triso and quartets. How many children were in the yard when Annie came to them?
- Do you solve this?
Determine area S of rectangle and length of its sides if its perimeter is 96 cm.
- Rhombus diagonal
Area of rhombus is 417. One diagonal measures 45, find length of other diagonal.
Fresh mushrooms contain 96% water, dried 12%. How many kg of fresh mushrooms is needed to collect to get 7 kg dried?
One half of rope use Mam for packaging, half of the rest got son, half of the rest he took father and two fifths of what remained, got daughter. Remained 52 cm of rope. How long was rope at the beginning?
- IS trapezoid
Calculate the length of diagonal u and height v of isosceles trapezoid ABCD, whose bases have lengths a = |AB| = 26 cm, c = |CD| = 5 cm and legs b = d = |BC| = |AD| = 19 cm.
The elections attended a total 4436 voters. First day 32 men more than women, the second day 38 women more than men. How many women attended elections?
In the dining room at one table sit Thomas, Filip and Martin. Together they eat 36 donuts. How many donuts eaten everyone, when Filip ate twice as much as Thomas and Martin even half over Filip?
The first tributary fill pool with water in 15 hours. The second tributary fill pool in 10 hours. For how many hours the pool is filled with both tributaries?