# Examples for 8th grade - page 81

- Sum of three numbers

The sum of three numbers from which second number is 20% smaller than the first number and the third number is 25% smaller than the second number is 96. Determine this numbers. - Two ages

Gabrielle is 9 years younger than Mikhail. The sum of their ages is 87. What is Mikhail's age? - Profitability

The purchase price of goods is 13000, the sales price is the 20000. What is the profitability as a percentage? - Iron cast

What is the weight of cast iron with volume 3575 cubic centimeters. The density of the cast iron is 7600 kg/m3 - Calf

The weight of the calf meat obtained is 65% of the total weight of live calves. What was the weight of a calf from which 285 kg of meat was obtained? - Three children

3 children eat 8 chocolates in 6 days. How many chocolates 6 children eat in 18 days? - Hydrostatic force

What hydrostatic force is applied to an area of 30 cm^{2}in water at a depth of 20 m? (Water density is 1000 kg/m3) - Regular quadrilateral pyramid

Find the volume and surface of a regular quadrilateral pyramid if the bottom edge is 45 cm long and the pyramid height is 7 cm. - Loading car

The car was loaded with 78 boxes weighing 19 kg. How many 25kg boxes can load if the total weight is the same? - Ice cream

Annie likes much ice cream. In the shop are six kinds of ice cream. In how many ways she can buy ice cream to three scoop if each have a different flavor mound and the order of scoops doesn't matter? - Potatoes 6

The farmer brought potatoes to the market. In the first hour he sold two-fifths of the potatoes brought, in the second hour he sold five-sixth of the remaining potatoes, and in the third hour he had sold the last 40kg of potatoes. How many kg of potatoes d - Ace

The length of segment AB is 24 cm and the point M and N divided it into thirds. Calculate the circumference and area of this shape. - Wide field

The field is 203 meters wide 319 meter long, what is the greater length of the rope by which length and width can be measured and find the exact number of time. - Circle r,D

Calculate the diameter and radius of the circle if it has length 52.45 cm. - Euros

Peter, Jane and Thomas have together € 550. Tomas has 20 euros more than Jane, Peter € 150 less than Thomas. Determine how much has each of them. - Kite

John a kite, which is diamond shaped. Its diagonals are 60 cm long and 90 cm long. Calculate: a) the diamond side b) how much paper John needs to make a kite if he needs paper on both sides and needs 5% of the paper for bending. - Metals

In the Hockey World Cup play eight teams, determine how many ways can they win gold, silver and bronze medals. - 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. - Midpoints

Triangle ABC with sides a = 5 cm, b = 3 cm, c = 40mm has a midpoint of K, L, M. How many centimeters is long perimeter of parallelogram KBLM? - Ages

John, Teresa, Daniel and Paul have summary 56 years. Their ages are in a ratio of 1:2:5:6. Determine how many years have each of them.

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