# Examples for 9th grade - page 12

- Sand pile

Auto sprinkled with sand to approximately conical shape. Workers wanted to determine the volume (amount of sand) and therefore measure the circumference of the base and the length of both sides of the cone (over the top). What is the volume of the sand c - Win in raffle

The raffle tickets were sold 200, 5 of which were winning. What is the probability that Peter, who bought one ticket will win? - Five tractors

Five tractors plow field in 4.8 hours. How long plow this field if after 1.5 hours of work two tractors went to a different field? - Chess

How many ways can select 3 fields on classic chess board with 64 fields, so that fields don't has the same color? - Tributaries

The first tributary fill pool with water in 15 hours. The second tributary fill pool in 10 hours. For how many hours the pool is filled with both tributaries? - Ladislav in Amsterdam

Ladislav was reward and went to conference in Amsterdam. Conferense fee was € 2184. Calculate how many books Ladislav could buy at the price of 42 and 28 euros if he don't want fill whole home library and he can buy only 63 books? - Combinatorics

The city has 10 fountains. Works only 7. How many options are there that can squirt ? - Arm

Calculate the length of the arm r of isosceles triangle ABC, with base |AB| = 16 cm and a height v=10 cm. - Olympics metals

In how many ways can be win six athletes medal positions in the Olympics? Metal color matters. - 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. - Reciprocal

What is the reciprocal of the sum of the reciprocals of 7 and 2? - VAT

John paid 1000 Euros in store for purchase. Calculate value added tax (VAT), which paid in purchase, if the VAT rate is 20%. - 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? - Gold coin

Gold coin contains 963 promile pure gold, which is 8.39 g. What is the weight of coin in grams? - Bits, bytes

Calculate how many different numbers can be encoded in 16-bit binary word? - Pyramid Z8–I–6

Each brick of pyramid contains one number. Whenever possible, the number in each brick is lowest common multiple of two numbers of bricks lying directly above it. That number may be in the lowest brick? Determine all possibilities. - Water

On the lawn which has area 243 m^{2}rained 5 mm of water. How many liters of water rained? - Scouts

The boys from scout group traveled 3 days distance 105 km. Every day walked 1.3 km less than the previous day. How many kilometers scouts walked in the first day? - Newton's task

Grass grows in the meadow equally fast and evenly. It is known that 58 cows graze meadow for 30 days and 80 cows by 19 days. How many cows graze meadow for 6 days? - Hole

In the center of the cube with edge 15 cm we will drill cylinder shape hole. Volume of the hole must be 28% of the cube. What drill diameter should be chosen?

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