Reason + harmonic mean - practice problems
Number of problems found: 23
- Aircraft angines
The aircraft's two engines are enough to supply the fuel for five hours of operation. However, one of the engines has malfunctioned and thus consumes one-third more fuel. How long can the plane be in the air before it runs out of fuel? After an hour of ma - Water current
John swims upstream. After a while, he passes the bottle, and from that moment, he floats for 20 minutes in the same direction. He then turns around and swims back, and from the first meeting with the bottle, he sails 2 kilometers before he reaches the bo - Triangle 8320
Is there a triangle with heights of 4, 7, and 10 meters? - Uphill and downhill
The cyclist moves uphill at a constant speed of v1 = 10 km/h. When he reaches the top of the hill, he turns and passes the same track downhill at a speed of v2 = 40 km/h. What is the average speed of a cyclist?
- Four pavers
Four pavers would pave the square in 18 days. How many pavers do you need to add to the done work in 12 days? - Kilometers 7631 At 8:00, Peter set out on a hike at 5 km/h. At 9:12, Michal followed him on a bike at a speed of 20 km/h. At what time did Michal Petra run, and how many kilometers did he cover?
- Two cities
The car goes from city A to city B at an average speed of 70 km/h and back at an average speed of 50 km/h. If it goes to B and back at an average speed of 60 km/h, the whole ride will take 8 minutes less. What is the distance between cities A and B? - Express train
An international express train drove from Kosice to Teplice. In the first 279 km, the track was repaired; therefore, it was moving at a speed of 10km/h less than it was scheduled to drive. The rest of the 465 km trip has increased the speed by 8 km/h to t - Harvesters
The first harvester will harvest the grain from the field in 20 hours, and the second, the more powerful, will harvest it in 10 hours. How long will it take for both harvesters to harvest this field if the second harvester has to be set up first, which ta
- Minutes 7177
The tank holds 140 liters of water. It is filled with a tap in 5 minutes, and the drain is emptied in 7 minutes. How long will it take for the empty tank to fill if we open the faucet and drain it? - ICE train
German runways test a new ICE train between Munich and Berlin. The train runs to Berlin at a slow speed of 110 km/h. Back from Berlin goes faster. How quickly did the train have to go on a return trip so that the average train speed for both journeys woul - Mow the lawn
Dano would mow the lawn in 12 hours and Milada in 16 hours. How long will it take the lawn mow together? - Oil tank and pipes
Two oil pipelines can fill the underground oil tank. The first is filled in 72 hours, and the second in 48 hours. How many hours from when the first pipeline began to fill the oil is necessary to start filling it with the second to fill in 1 and 1/2 days? - Average speed
The first third of the track was driven by a car at a speed of 15 km/h, the second third at a speed of 30 km/h, and the last third at a speed of 90 km/h. Find the average speed of the car.
- Timber log
The ship goes from point x to y. Downstream it takes 4 hours, and upstream 6 hours. How long does it take from a point x to y a log? - Three drivers
Three drivers driving in the same direction found that they had the same amount of gasoline. The first is enough to go 6 km, 4 km, second and third 3km. Gasoline they divided, so all three just drove to the nearest petrol station. How many km away was a p - Forth and back
The car drives from point A to point B at 78 km/h speed and back at 82 km/h. If I went there and back at a speed of 81 km/h, the journey would take five minutes less. What is the distance between points A and B? - Simultaneously 2570
Two cyclists will set off simultaneously from one place on the circular cycling track. How long before they meet? Do you know that Karel will drive in 6 minutes and Laco in 10 minutes? - Drinking water
A man drinks a keg of water in 21 days, and a woman drinks in 43 days. How many days do they consume a keg together?
If water flows into the pool through two inlets, it will fill for 5 hours. If the first inlet fills the pool 5 hour longer than the second, how long does it take to fill with two inlets separately?Do you have unsolved problem that you need help? Ask a question, and we will try to solve it. Solving math problems.
