# Examples for 8th grade - page 71

- Runner

Peter ran a speed of 12.4 km / h. After 45 minutes running he had a hiatus. The track is 31 km long. How many kilometers he still to run if he still running at the same speed? - Simply equation

Solve this equation for x: ? - Mass

The thickness of a metallic tube is 1cm and its outer radius is 11cm. Find the mass of such 1m long tube, if the density of the metal is 7.5g per cubic cm. - Steamer

At 6 hours 40 minutes steamer sailed from the port at speed 12 km/h. At exactly 10 hours started sail motorboat at speed 42 km/h. When motorboat will catch steamer? - Numbers

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

Mrs. Violet brewed 15 l of raspberry juice. She poured it into 17 bottles. Some were 3/4 liter and some one liter. How many was bottles of this two types? - Sweets

We want to prepare 5 kg of sweets for 150 CZK. We will mix cheaper candy: 1 kg for 120 CZK and more expensive candy: 1 kg per 240 CZK. How much of this two types of candy is necessary to prepare this mixture? - Three ints

The sum of three consecutive integers is 2016. What numbers are they? - Apples 2

James has 13 apples. It has 30 percent more apples than Sam. How many apples has Sam? - Circle and rectangle

A rectangle with sides of 11.7 cm and 175 mm is described by circle. What is its length? Calculate the content area of the circle described by this circle. - Prism

Calculate the height of the prism having a surface area 448.88 dm² wherein the base is square with a side of 6.2 dm. What will be its volume in hectoliters? - Cakes

Grandmother baked cakes. Half of its was poppy, quarter with plum jam and 16 cheesecakes. How many cakes she baked in total? - One-third

A one-third of unknown number is equal to five times as great as the difference of the same unknown number and number 28. Determine the unknown number. - Savings and retirement

The older sibling has saved 44% more euros than the youngest, which represents 22 euros. How many euros older brother has saved ? - Percentage - fractions

About what percentage we must increase number 1/6 to get number 1/3? - Joshka

Joshka had € 15. Mama took him 15%. How many had left? - Apples 2

How many apples were originally on the tree, if the first day fell one third, the second day quarter of the rest and on tree remained 45 apples? - Password dalibor

Kamila wants to change the password daliborZ by a) two consonants exchanged between themselves, b) changes one little vowel to such same great vowel c) makes this two changes. How many opportunities have a choice? - Algebrogram

Solve algebrogram: mama+anna=vari How many solutions are? - Cylinder twice

If the radius of the cylinder increases twice, and the height is reduced twice, then the volume of the cylinder increases (how many times?):

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