# Examples for 8th grade - page 31

- Unknown number 5

I think unknown number. If we enlarge it five times then subtract 3 and result decreases by 75% we get the number by one greater than the number I think. What number am I thinking? - Eva

When Eva buys 8 packages of cookies 4 CZK left her. If she wanted to buy 10 packages, she would have to borrow 20 CZK. How much money has Eva in her wallet? - Ski lessons

On the ski course leaves 80 pupils. They live in triple and quadruple rooms. Count if rooms is the 23. How many are triple and quadruple rooms? - Nuts, girl and boys

Milena collected fallen nuts and called a bunch of boys let them share. She took a condition: the first boy takes one nut and tenth of the rest, the second takes 2 nuts and tenth new rest, the third takes 3 nuts and tenth new rest and so on. Thus managed. - Liters in cylinder

Determine the height at which level 20 liters of water in a cylindrical container having a bottom diameter 29 cm. - Pizza

Pizza with a diameter 41 cm have weight 531 g. What diameter will have a pizza weighing 749 g if it is make from the same cloth (same thickness....) and same decorated? - Arc

The length of the circle is 33 amd arc length of the circle 11. What is the magnitude of the angle of this arc? - Typing course

Before taking a typing course, Seth could type 30 words per minute. By the end of the course, he was able to type 66 words per minute. Find the percent increase. - Gasoline

For nearly full tank of 40 liters of gasoline chauffeur paid 54 euros. How many euros it will cost to go 250 km long if the car has an average fuel consumption 7 liters per 100 kilometers? - Raspberries

Dano had 20 raspberries. John had 90% more raspberries than Dano. Determine how many raspberries have Dano and Juraj together. - 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?): - 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? - Rectangle

The perimeter of the rectangle is 22 cm and content area 30 cm^{2.}Determine its dimensions, if the length of the sides of the rectangle in centimeters is expressed by integers. - Three friends

Divide 570 euros to three friends so that first will get 50 euros less than the second and third twice more than the first. How many euros will get everyone? - The book

If one day you read p pages, you will read the book 24 days. If you read each day 10 pages more, you would read a book in 16 days. How many pages have the book? - Liters od milk

The cylinder-shaped container contains 80 liters of milk. Milk level is 45 cm. How much milk will in the container, if level raise to height 72 cm? - Stock

Enterprise sold 7/12 of their products to foreign markets and 2/5 of the remainder sold at home. How many % of the products is still in stock? - Stairs

Between adjacent levels are 15 stairs. If step will be 1.2 cm lower there would be 16 stairs. What is the stair height? - 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? - Alloy

The first alloy is a mixture of two metals in the ratio 1:2, the second is a mixture of same metals in the ratio 2:3. At what ratio we have these two alloys put into the furnace to obtain a new metal alloy with ratio 17:27? (All three ratios correspond to.

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