# Examples for 9th grade - page 80

- Sphere radius

The surface of the sphere is 60 cm square. Calculate its radius; result round to tenth of cm. - Sales off

shoes cost x euros. First they are discounted by 50%, and then 25% of the new amount. Determine what percentage of the total cost is cheaper. - RT perimeter

The leg of the rectangular triangle is 7 cm shorter than the second leg and 8 cm shorter than the hypotenuse. Calculate the triangle circumference. - Acres

Two hours 24 students harvested chestnuts on 36 acres. How many square meters harvested one student per hour? - Trapezoid - central median

The central median divides the trapezoid into two smaller trapezoids. Determines the ratio of their contents. - Prize

How many ways can be rewarded 9 participants with the first, second and third prize in a sports competition? - 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? - Fifth member

Determine the fifth member of the arithmetic progression, if the sum of the second and fifth members equal to 73, and difference d = 7. - Rectangle 35

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

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

The cross-section ABCD of a swimming pool is a trapezium. Its width AB=14 meters, depth at the shallow end is 1.5 meters and at the deep end is 8 meter. Find the area of the cross-section. - Road drop

On a straight stretch of road is marked 12 percent drop. What angle makes the direction of the road with the horizontal plane? - 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. - 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 - Boys and money

270 USD boys divided so that Peter got three times more than Paul and Ivan has 120 USD more than than Paul. How much each received? - 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. - 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.

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