# Examples for 8th grade - page 26

- 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? - Container

First day got off 1/4 water from full container, second day 1/5 of the remaining water. How many percent remain container filled? - Equation with fractions

Solve equation: ? It is equation with fractions. - Alcohol 2

Two types of alcohol one 70% and second 61% give 11 liters of 57% alcohol. How many liters of each type are in the mixture? - Thales

Calculate the length of the Thales' circle described to right triangle with hypotenuse 44 cm. - Bakery

How heavy must prepare bread at a bakery if lose during baking 14% of water and after baking must have 1.6 kg? (Calculate to the nearest gram) - Cuboid

The cuboid has a surface area 8710 cm^{2,}the length of its edges are in the ratio 3:2:1. Calculate the volume of the cuboid. - Barrel with liquid

Barrel with grain weight 263 kg. When it shed 43% of grain, ha weight 170 kg. What is the weight of empty barrel? - Triangle angles

The angles α, β, γ in triangle ABC are in the ratio 10:5:6. Calculate size of angles. - Apples in baskets

Determine how many apples are in baskets when in the first basket are 4 apples, and in any other is 29 apples more than the previous, and we have eight baskets. - Grass garden

Mr. Grass would itself be mowed garden for 5 hours. His son Michael could do it for 7 hours. They agreed that they wake up at 5 am and begins to mow together. Ms. Grass needs drive into town at 8.30. Michael says that at that time they're done with work.. - Trrops - soldiers

Food stocks will last 20 soldiers of the 4-day training. How many days they could extend training if four soldiers become sick? - Floating floor

In the new building is considered a floating floor worker in each room. 30 minutes lay 9 m^{2}of the floor. How long 3 workers laid the floor in 4 rooms with a total area of 90 m^{2}? - Father and son

Father is three times older than his son. 12 years ago father was nine times older than the son. How old are father and son? - Comparing powers

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

Mr. Peter build a pool shape of a four-sided prism with rhombus base in the garden. Base edge length is 6 m, distance of the opposite walls of the pool is 5 m. Estimated depth is 193 cm. How many hectoliters of water consume Mr. Peter to fill the pool? - Work

First paver pave pavement for 33 hours. Second for 24 hours. Started first paver and after 5 hours, join the second. How long will they finish pavement? - Vinegar

We must dilute 80 liters of 7.6% aqueous vinegar to 4.2% one. How much water is necessary to add?

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