# Examples for 8th grade - page 61

- New refrigerator

New refrigerator sells for 878 USD, Monday will be 25% discount. How much USD will save, and what will be the price? - Three numbers

Find three numbers so that the second number is 4 times greater than the first and the third is lower by 5 than the second number. Their sum is 67. - Solutions

How much 60% solution and how much 35% solution is needed to create 100 l of 40% solution? - Square garden

On the plan with a scale of 1:1500 is drawn as a square garden with area 4 cm^{2.}How many meters is long garden fence? Determine the actual acreage gardens. - Mrs XY

Mrs Novak is employed. In January 2015 the gross income reached € 1193. Insurance is a 286.32 euros, and income taz 136 euros. Employer precipitated Mrs. Novak in recent clashes € 142, of which 64 euro for the savings account, and 78 euros for repayment of - Surface area 2

Calculate how many % reduce the surface area of the cube is we reduced length of each edge by 10%. - Tower model

Tower height is 300 meters, weight 8000 tons. How high is the model of the tower weight 1 kg? (State the result in the centimeters). The model is made from exactly the same material as the original no numbers need to be rounded. The result is a three-digi - Borrowed book

Jane must as soon as possible return a borrowed book. She figured that when she read 15 pages a day return book in time. Then she read 18 pages a day and then return the book one day before. How many pages should have a book? - Sines

In ▵ ABC, if sin(α)=0.5 and sin(β)=0.1 calculate sin(γ) - 7 roses

Peter buys 7 roses. When he pay for it left him 4 euro. If he bought 5 roses left him 40 euros. How many euros had Peter before buying? - Runners circle

Pepa circles the track in 36 seconds. Kamil in 42 seconds. They started together. How many seconds will meet again at the start? - Coffee shop

To the coffee shop brought 2 types of coffee totally 50 kg. The first type was CZK 220 per kilogram, coffee second type 300 CZK per 1 kg. For all the coffee trader earned CZK 12,000. How many kilograms of coffee of first type and how many kilograms of cof - The tent

The tent shape of a regular quadrilateral pyramid has a base edge length a = 2 m and a height v = 1.8 m. How many m^{2}of cloth we need to make the tent if we have to add 7% of the seams? How many m^{3}of air will be in the tent? - Rhombus and diagonals

The a rhombus area is 150 cm^{2}and the ratio of the diagonals is 3:4. Calculate the length of its height. - Mother and daughter

The ratio of years mother and daughter is 5:2. After 7 years the ratio is 2: 1. How many years ago daughter was born? - Three dice

When you throw three dice was the sum total of the dice 10. The yellow dice fell one eye more than on the red and brown fell 3 eyes less than red. How many eyes fell on every dice? - Sinus

Determine the smallest integer p for which the equation 5 sin x = p has no solution. - Mushrooms

For five days, we have collected 410 mushrooms. Interestingly every day we have collected 10 mushrooms more than the preceding day. How many mushrooms we have collected during 4th day? - Gearing

Gearing consists of two wheels, one is 88 and second 56 teeth. How many times turns smaller wheel to fit the same teeth as in the beginning? How many times will turn biggest wheel? - Farm2

The farm bred turkeys, geese, hens and chickens. Everything is 400. Turkeys and geese a hen are 150. No hen has more than one chicken, but some hens has no chick. Half of them is also a quarter of the chickens. When the turkey subtracting 15, we get 75. Ho

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