# Examples for 8th grade - page 42

- Pair

They have together 39 years - he has 2 times as she was when he was equal as she has today .... - The dam

The water reservoir is filled with first tributary for 25 hours second tributary for 35 hours. Some time were both inlets open, then a second tributary closed and the tank was filled in four hours. What time water flowed from both tributaries? (Expressed i - Homework

Mother and Kate together weigh 24.5 kg more than the father. Father weighs 7.6 kg more than mother. Father weight 44.8 kg more than Kate. Determine weights of father mother and Kate. - Garage

There are two laths in the garage opposite one another: one 2 meters long and the second 3 meters long. They fall against each other and stay against the opposite walls of the garage and both laths cross 70 cm above the garage floor. How wide is the garag - Workers

Ten workers must pave road street for 22 working days. After four days were for speeding up work added two more workers. a) After how many work days now workers completes the paved road? b) How many working days it took a total paved road? - Shoes

Peter decided to measure shoes size of his three friends. Measured accurately and wrote as follows: Venda and Jenda together 52 cm Jenda and Zdenda together 58 cm Zdenda and Venda together 54 cm a) How long measures Vendy, Jenda and Zdenda shoes together - Roots

Calculate the square root of these numbers: - Cosine

The point (8, 6) is on the terminal side of angle θ. cos θ = ? - Lamp cone

Calculate the surface of a lamp shade shaped of a rotary truncated cone with base diameter 32 cm and 12 cm and height 24 cm. - 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? - 6 regular polygon

It is given 6 side regular polygon whose side is 5 cm. Calculate its content area. Compare how many more cm^{2}(square centimeters) has a circle in which is inscribed the 6-gon. - Pipe

How long is the pipe with an outside diameter of 1.44 m if his coloring consumed 44 kg of color. 1 kg of color coverage is 9 m^{2}. - Two trains

Two trains go at each other. First at speed 40 km/h and the second at speed 60 km/h. At what distance will be 30 minutes before they will meet? - Tank No 8

Tank is filled by one inlet valve with a flow rate of 12 liters per second in 72 minutes. How long take the tank to fill, if we open half an hour after one more inlet? - Water level

The glass container has a cuboid shape with dimensions of the bottom 24 cm and 12 cm. The height of water is 26 cm. Calculate the volume of the body, which are sunk into the water if the water level rise by 3 cm. - Water reservoir

The water reservoir is filled with one pump for 4 days by the second one for 9 days. Outlet can drain tank in 12 days. How long take fill the reservoir if both pumps are running and not closed outlet channel. - Median

In triangle ABC is given side a=10 cm and median ta= 13 cm and angle gamma 90°. Calculate length of the median tb. - Inscribed triangle

To a circle is inscribed triangle so that the it's vertexes divide circle into 3 arcs. The length of the arcs are in the ratio 2:3:7. Determine the interior angles of a triangle. - Water level

How high reaches the water in the cylindrical barell with a diameter of 12 cm if there is a liter of water? Express in cm with an accuracy of 1 decimal place. - Blackjack TU160

Bomber Tupolev TU160 started at 9:00 from the airport and flew at average speed of 1850 km/h toward the airfield B distant 3500 km. After evaluating the danger from the airport B started at 9:45 B towards A fighter MIG 29 at an average speed 2300 km/h. At

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