# Examples for 7th grade (seventh) - page 19

- Divisibility

Determine all divisors of number 84. - Racing track

On the racing track circling three cars. The first passes one circuit for 8 seconds, the second for 20 seconds and a third for 8 seconds. a) Calculate number of seconds since the start to catch all three cars together for the first time again across the s - Farmer

The farmer farming 293 ha of arable land and the remaining 20% are meadows and pastures. How much land farmer owns? - Stones in aquarium

In an aquarium with a length 2 m; width 1.5 m and a depth of 2.5 m is a water level up to three-quarters of the depth. Can we place stones with a volume of 2 m^{3}into the aquarium without water being poured out? - Honza + Alice + Tonda

Honza + Alice + Tonda have a total of 111 USD. The ratio between Honza and Alena is 5:6 and the ratio between Alice and Tonda is 4:5 How many money have each of them? - Number train

The numbers 1,2,3,4,5,6,7,8 and 9 traveled by train. The train had three cars and each was carrying just three numbers. No. 1 rode in the first carriage, and in the last carriage was all odd numbers. The conductor calculated sum of the numbers in the first - Bridge

The bridge arc has a span 235 m and height 3 m. Calculate the radius of the circle arc of this bridge. - Car

The driver of a car is to get to 608 km distant city. From atlas found that 162 km will have to pass through the cities at average speed 48 km/h. Remainder of the journey pass outside the cities at average speed 116 km/h. Calculate how many hours it will t - Apples

Mr. Vesely give to the market his own 48 kg of apples, 40 kg from Mr. Kovar and 72 kg of Mr. Novak. Grossed a total of 1,920 CZK. How must divide income money for apples? - Two diggers

There are two diggers. One digger digs a pit 46 hours second gidding 2 times faster. a) how long took to dig a pit second digger b) how long took dig together - Cuboid 5

Calculate the weight of the cuboid with dimensions of 12 cm; 0.8 dm and 100 mm made from spruce wood (ς = 550 kg/m^{3}). - Percentages and numbers

How many percent is number 426 greater than number 71? - Crown

Siblings collect a 2-crowns and 5-crowns. Together have 80 coins with a total of value 310 crowns. How many saved two-crowns and how many five-crowns? - Mountain railway

Height difference between points A, B of railway line is 38.5 meters, their horizontal distance is 3.5 km. Determine average climb in permille up the track. - Lorry

The lorry was loaded with 18 boxes of 15 kg. How many boxes with weight 18 kg can be loaded, if total load must be same? - Divers

20-member group of divers carries the air for 15 hours of diving. 4 members of the expedition sick or wasn't came. How many hours is sufficient air to other divers? - Grandson and granddad

Grandson with grandpa they counted how many years have together. Their product is 365. How many years is the sum of their years. - Iron fence

One field of iron fence consists of 20 iron rods with square cross-section of 1.5 cm side and a long 1 meter. How much weight a field if the density of iron is 7800 kg/m^{3}. - Racer

The first racer run at a speed 20 m/s and is 750 meters before the finish and ahead 79 meters before second competitor. At what speed must run the second racer to catch first racer at the finish line? - Sawdust

How many cubic centimeters of wood sawdust is created by cut the tree trunk with a diameter of 66 cm and when the gap width is 5 mm?

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