Examples for 8th grade - page 47

A three-digit numbers
Determine the total number of positive three-digit numbers that contain a digit 6.
Plums
In the bag was to total 136 plums. Igor took 3 plums and Mary took 4/7 from the rest. How many plums remained in the bag?
Water in aquarium
The aquarium cuboid shape with a length of 25 cm and a width of 30 cm is 9 liters of water. Calculate the areas which are wetted with water.
10 pieces
How to divide the circle into 10 parts (geometrically)?
Znojmo
From Znojmo to Brno started truck with a trailer at an average speed 53 km per hour. Against him 14 minutes later from Brno started car with an average speed of 1.2-times greater than the truck. How long and how far from Znojmo, they meet if the distanc
Direct route
From two different places A and B connected by a direct route, Adam (from city A) and Bohus (from city B) started at a constant speed. As Adam continued to go from A to B, Bohus turned around at the time of their meeting and at the same speed he returned t
Algebrogram
Solve algebrogram for sum of three numbers: BEK KEMR SOMR ________ HERCI
Soup
47% of pupils at the school to eat in the canteen, 1/47 of students who eat in the canteen eat lunch soup. a) What percentage of pupils who eat in the canteen and eat soup for lunch? b) What percentage of all pupils of school eat lunch soup?
Two pumps
The first pump fills the tank in 24 hours second pump in another 40 hours. For how long will take fill the tank if operate both pumps at the same time?
Right triangle - leg
Calculate to the nearest tenth cm length of leg in right-angled triangle with hypotenuse length 9 cm and 7 cm long leg.
Great Wall of China
Great Wall of China is long 8880 km. Historically valuable however is only 30% of its length. What amount of insurance pays the Peoples Republic of China a month for this monument, if the insurance company charges $ 10 per year per kilometer of historic s
Flowerbed
On the flowerbed was planted 280 flowers - pansies and crayons. During the first week wilts quarter of pansies and an eighth crayons, which is 20% of all flowers. How many pansies were planted on the flowerbed?
Brackets
Place one pair of brackets in expression 20-16 + 10 - 4 - 2 so that the result will be 0.
Mukls
The working group, in which 6 workers would ordered job completed within 21 working days. How many workers must be accept yet that the contract will be completed in 14 working days?
Harvesters
The first harvester reaps the grain from land for 24 hours, the second harvester for 16 hours. For how many hours will take harvest by two harvesters, but the second harvester started working four hours later than the first?
Buses
Buses Ikarus and Karosa simultaneously started at 8:00 from the final station. Ikarus is returned to the station after 30 minutes. Karosa after 45 minutes. At what time both buses again returned to the station?
Center of gravity
In the isosceles triangle ABC is the ratio of the lengths of AB and the height to AB 10:12. The arm has a length of 26 cm. If the center of gravity T of triangle ABC find area of triangle ABT.
Medians in triangle
Median of isosceles triangle has a length 3 cm. Determine the length of its sides if its perimeter is 16 cm.
Influenza
For the first week of February by influenza 5% of children in kindergarten. The second week ill 9 next children, bringing the number of patients increased to 20%. How many children went to the kindergarten?
VAT
In the country XYZ car Daewoo Leganza costs 3748 Euros including VAT; 3335.72 Eur without VAT. a) Determine the rate of VAT. b) How much is Euro VAT paid on the purchase? c) How many % of the total price of the goods is VAT? VAT = value added tax.

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