# Examples for 8th grade - page 88

- Rectangle 35

Find the area of a rectangle when the diagonal is equal to 30 cms and the width is double the length. - Apples

Apples I picked 600 kg this year. Autumn's apples was 4 times more than the summer. How many kg's I picked the summer and how much winter apples? - The rectangle

Determine the area of the rectangle where the length and width are in the ratio 5:2 and its length is 7.5 cm longer than its width. Determine also its length and its width. - One percent

One percent of all the lights in the city are LED, the remaining 99% are conventional. Other types are not there. John counted them honestly but he had counted only conventional. After a good dinner he registered numbers and he have notice that from all t - Pond

A pond with two open floodgates will emptied in 20 days. A larger floodgate will emptied whole pond in 30 days. For how long would he be emptied with a smaller floodgate. - Unknown number x

5% from an unknown number equals the number 2^{6.}What is the unknown number? - Ravens

On two trees sitting 17 ravens. If 3 ravens flew from first to second tree and 5 ravens took off from second tree then the first tree has 2 times more ravens than second tree. How many ravens was originally on every tree? - Walnuts

x walnuts were in the mission. Dano took 1/4 of nuts Michael took 1/8 from the rest and John took 34 nuts. It stayed here 29 nuts. Determine the original number of nuts. - Linear system

Solve this linear system (two linear equations with two unknowns): x+y =36 19x+22y=720 - Efficiency

What is the power output of kettle 2 kW with efficiency 90%? - Way

If the current way to school was 2 km shorter then if Milan swipe one half he will have already one quarter of the way to school behind. How long is Milan's way to school? - Two aircraft

From the airport will start simultaneously two planes, which fly tracks are perpendicular to each other. The first flying speed of 680 km/h and the second 840 km/h. Calculate how far the aircraft will fly for half an hour. - Candies

There are red, blue and green candies in bad. Red to green is in 6:11 ratio and blue to red in a 7: 5 ratio. In what proportion are blue to green candies? - Socks

One pair of socks worth CZK 27. Set of 3 pairs of these socks are sold with 10% discount. How many we will pay CZK for two offered sets of socks? - Stairway

Stairway has 20 steps. Each step has a length of 22 cm and a height of 15 cm. Calculate the length of the handrail of staircases if on the top and bottom exceeds 10 cm. - Volume increase

How many percent will increase in the pool 50 m, width 15m if the level rises from 1m to 150cm? - Price increase

A 20 percent price increase meant a 90-crown raise. How many cost a product after? - Working together on project

Two employees working on the project. First make it alone for 20 days the second for 24 days. How many days will take to complete project if 5 days they work together then first will take two days holiday and after returning they completes a project toget - Regular n-gon

In a regular n-angle polygon the internal angle is 144 degrees. Find the number n indicating the number of sides of this polygon. - Plane II

A plane flew 50 km on a bearing 63degrees20 and the flew on a bearing 153degrees20 for 140km. Find the distance between the starting point and the ending point

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