# Examples for 8th grade - page 32

- Tunnels

Mice had built an underground house consisting of chambers and tunnels: • each tunnel leading from the chamber to the chamber (none is blind) • from each chamber lead just three tunnels into three distinct chambers, • from each chamber mice can get to any - The body

The body on the figure consists of cubes with an edge length 10 cm. What surface has this body? - Addends

Number 839 divide into the two addends that the first was 17 greater than 60% of the second. Determine these addends. - SAS triangle

The triangle has two sides long 7 and 19 and included angle 36°. Calculate area of this triangle. - Katy MO

Kate draw triangle ABC. Middle of AB have mark as X and the center of the side AC as Y. On the side BC wants to find the point Z such that the content area of a 4gon AXZY was greatest. What part of the triangle ABC can maximally occupy 4-gon AXZY? - Mother and daughter

Three years ago mother was three times older than daughter. After nine years she will be only twice old. How old is mother (and daughter)? - Exam average

Average of marks that have on the certificates students of 8.A class in mathematics is exactly 2.45. If we did not add 1 and 3 of sutdents Michael and Alena, who arrived a month ago, it would average exactly 2.5. Determine how many students have class 8. - Warehouse cars

From the warehouse started truck at speed 40km/h. After 1hour 30mins started from the same place same direction a car at speed 70 km/h. For how long and at what distance from the warehouse overtake a truck? - 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? - Chess

How many ways can select 4 fields on classic chess board with 64 fields, so that fields don't has the same color? - Suit

The suit cost 119 euros. How much cost the pants if it is 50% cheaper than the jacket. - VAT

VAT is a tax which the state artificially betrays goods and services for final consumption. VAT in Slovakia is 20%. Calculate how much percent pay less tax residents of Liechtenstein, when VAT is only 8%. - Sprayers

The vineyard can be sprayed first sprayer in 5 hours and with the second in 8 hours. How long would it take if we use sprayers both at once? - Work

First paver pave pavement for 27 hours. Second for 27 hours. Started first paver and after 4 hours, join the second. How long will they finish pavement? - Gasholder

The gasholder has spherical shape with a diameter 20 m. How many m^{3}can hold in? - Seven-segmet

Lenka is amused that he punched a calculator (seven-segment display) numbers and used only digits 2 to 9. Some numbers have the property that their image in the axial or central symmetry was again give some number. Determine the maximum number of three-d - Grandfather

The grandfather is three years older than an grandmother. The average age of the grandmother, the grandfather and their seven grandchildren is 28 years. The grandchildren have a total of 105 years. Calculate how old is grandfather. - Bath

In the bath is 30 liters of hot water. Then added 36 liters of cold water at temperature of 19 °C decreased temperature of water to 41 °C. What was the initial temperature of the hot water? - 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? - Diamond

Side length of diamond is 35 cm and the length of the diagonal is 56 cm. Calculate the height and length of the second diagonal.

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