# Examples for 9th grade - page 47

- Unknown number

Unknown number is divisible by exactly three different primes. When we compare these primes in ascending order, the following applies: • Difference first and second prime number is half the difference between the third and second prime numbers. • The produ - Square ABCD

Construct a square ABCD with cente S [3,2] and the side a = 4 cm. Point A lies on the x-axis. Construct square image in the displacement given by oriented segment SS'; S` [-1 - 4]. - Cube 7

Calculate the volume of a cube, whose sum of the lengths of all edges is 276 cm. - Chords

How many 6-tones chords (chord = at the same time sounding different tones) is possible to play within 10 tones? - Two numbers

The sum of two numbers is 1. Identify this two numbers if you know that the half of first is equal to the third of second number. - Sputnik

The first Earth satellite was flying at speed 8000 m/s. At that rate he circled the earth in 82 minutes. Jet flies at an average speed 800 km/h. How long would it take circle the earth round? - Cube from sphere

What largest surface area (in cm^{2}) can have a cube that was cut out of a sphere with radius 22 cm? - Price reduction

Price of camera is 800 USD on sale its price reduced to 423 USD. Calculate the percentage reduction in the price of the camera. - Circle and hexagon

Calculate the radius of a circle whose circumference is 6.8 cm longer than the circumference of the inscribed regular hexagon. - ABS

What is the value of ? ? - High wall

I have a wall 2m high. I need a 15 degree angle (upward) to second wall 4 meters away. How high must the second wall? - Two trains meet

From A started at 7:15 express train at speed 85 km/h to B. From B started passenger train at 8:30 in the direction to A and at speed 55 km/h. The distance A and B is 386 1/4 km. At what time and at what distance from B the two trains meet? - Tent

Calculate how many liters of air will fit in the tent that has a shield in the shape of an isosceles right triangle with legs r = 3 m long the height = 1.5 m and a side length d = 5 m. - Mother and daughter 2

The mother is 40 years older than her daughter. How old is the mother if her age is eight thirds age of daughter? - 10 pieces

How to divide the circle into 10 parts (geometrically)? - 5 pumps

Five pump to pump 3 hours 1600 hl of water. How long pumped same amount of water 4 pumps? - Equilateral triangle v2

Equilateral triangle has a perimeter 36 dm. What is its area? - Sisters

Sisters Zuzka Lenka and Vierka has save for a new bike. Zuzka save € 90, Lenka save € 90 and Vierka save € 82. Missing 30% gave them their mother. What is the price of the bike? - Parachutists

Parachutists during freefall firstly held in groups of 4, then of 6, then 9, 12 and finally of 18 members. How many parachutists jump at least should be, if at each group must all be involved. - Three men

Alex is half younger than Jan, which is one-third younger than George. The sum of their ages is 48. How are these three men old?

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