# Examples for 8th grade - page 32

- Bronze, tin and copper

Bronze is an alloy of tin and copper. An alloy of 10% tin and 90% copper is Gunmetal. If it contains 20% tin and 80% copper, it is bell metal. How many tons of molten bell metal and how many tons of copper is needed to make 100 tons of Gunmetal? - Plum

On the platter are plum. How many were there if its have to be able to share equally among 8,10 and 12 children? - Spirit

From 55% and 80% spirit we would like to produce 0.2 kg of 60% spirit. How many of them we must use in a solution? - Bathroom

How many CZK we pay for lining the perimeter walls of the bathroom with rectangular shape with dimensions 3.5 m and 4 m, high 1.5 m if 1 square m tile cost 300 CZK? - 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? - Vacation

Parents piggybacking children on vacation to its grandmother and grandfather at a city distant 150 kilometers. They agreed to meet halfway. Parents will be travel at 90 km/h, grandmother and grandfather at 60 km/h. Parents depart at 12:00 hours. When grand - Water lake

The length of the lake water is 8 meters width 7 meters and depth 120 centimeters. How many liters of water can fit into the water lake? - Circle sector

Circular sector with a central angle 10 ° has area 254 cm^{2.}Calculate its radius r. - Painting school

Redecoration school had scheduled for four crew to 10 days. After two days a single worker ill. For how many days the school was painted when remain workers working with the same tempo? - Cargo

Weight of cargo car is 761 kg. Weight of car is 23% of the total weight of car+cargo. What is the weight of the cargo load? - Lenka and money

When Lenka bought pants from 1/3 of her savings shirt from 1/5 and 1/8 spent at the hairdresser, she is left 328 Kč. How much money was saved? How much hairdresser cost? - Parallelogram ABCD

The area of parallelogram ABCD is 41 cm^{2.}Points M and N are the midpoints of the sides AB and BC. What is the area of a quadrilateral MBND? - Circles

Area of circle inscribed in a square is 6. What is the area of a circle circumscribed around a square? - Cylinder - h2

Cylinder volume is 2.7 liters. Base area is 1 dm^{2.}Calculate the height of the cylinder. - Leveling

Calculate how many 25 kg bags of leveling concrete must be purchased if we leveling room 28 m^{2}to the "height" 12 mm if consumtion is 1.7 kg per square meter and millimeter thickness. - Comparing powers

How many times is number 5^{5}larger than number 4^{5}? - Circumferential angle

Vertices of the triangle ΔABC lies on circle and divided it into arcs in the ratio 5:5:3. Determine the size of the angles of the triangle ΔABC. - Balls

Three metal balls with volumes V_{1}=41 cm^{3}V_{2}=58 cm^{3}and V_{3}=83 cm^{3}melted into one ball. Determine it's surface area. - Sawdust

How many cubic centimeters of wood sawdust is created by cut the tree trunk with a diameter of 38 cm and when the gap width is 6 mm? - Homework - jumps

Sasha jumped 142 cm Peter 4 cm more than Jirka. Jirka 6 cm less than Misha. Misha 7 cm less than Filip and Filip half as much Sasha and Petr together. How far each jumped?

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