# Examples for 8th grade - page 31

- Scale

Cylinder was drawn in scale 7:1. How many times is the volume of the cylinder smaller in reality? - Equilateral triangle

How long should be the minimum radius of the circular plate to be cut equilateral triangle with side 7 mm from it? - Triangle TBC

TBC is isosceles triangle with base TB with base angle 52° and legs length |TC| = |BC| = 30. How long is the base TB? - Chord

In a circle with radius r=11 cm is chord 4× longer than its distance from the center. What is the length of the chord? - Efficiency

What is the power output of kettle 2 kW with efficiency 90%? - Pears

Andrew, Lenka and Rasto have together 232 pears. Lenka has 28 more than Rasto and Rasto pears have 96 more than Andrew. Determine how much each of them has pears. - Solution

What amount of 80% solution and what amount of water is needed to mix in order to obtain two liters of 60% solution of this mixture? - Liquid soap

Liquid soap lasted two weeks to one member of the family. How many days will last, if it use: a) two members b) 4 members c) seven members? - New computer

New computer process a certain amount of data for 6 hours. For how many hours will process the same amount of data older computer that has a quarter lower performance? - Apprentice

Worker and apprentice execute the work for 6 hours. Worker performs himself in 10 hours. How long do the work of an apprentice? - Three siblings

Three siblings have birthday in one day-today. Together they have 35 years today. The youngest is three years younger than middle and the oldest is 5 years older than middle. How old is each? - 12 Moons

Good Marry came to ask twelve moons for help with collecting strawberries. All twelve moons 1200 strawberries picked in 20 minutes. But lazy months July and August cease tear after 5 minutes. How many minutes in total will take collect strawberries? - Stone

When Peter threw stone in a box of water he discovered that the water level has risen by 8 cm. The box has a cuboid shape, the bottom has dimensions of 24 cm and 14 cm, height is 48 cm. What volume has a stone? - Borrowed book

Jane must as soon as possible return a borrowed book. She figured that when she read 15 pages a day return book in time. Then she read 18 pages a day and then return the book one day before. How many pages should have a book? - Numbers

Write smallest three-digit number, which in division 5 and 7 gives the rest 2. - Sisters

Sisters Janka and Danka are saved together 220 CZK. On a trip to Janka wants to take a fifth of her savings and Danka quarter. Then they will have 50 CZK on the trip. How much money saved Janka and Danka? - Parking

120 vehicles parking on the morning. Pasenger car is charged 20 CZK, 50 CZK per bus. The guard collected for parking 2640 CZK in total. How many cars and how many buses stood in the parking? - Plan scale

At what scale is drawn plan of the building, where one side of the building is 45 meters long is on the plan expressed by a straight line 12 mm long. - Chalet

The children were on a school trip to the mountain . One third of the journey went by the train and continue by bus. When you get off the bus, they remained a third of the distance they traveled by bus. What part of journey children went by the bus (wrote - Efficiency

A certain device consumes 93 kW and delivers 77 kW. Find its efficiency.

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