Harmonic mean - practice for 14 year olds - page 3 of 6
Number of problems found: 101
- Water current speed.
Two cities along the river are 100 km apart. The powerboat downstream runs for 4 hours, upstream for 10 hours. Determines the river's current speed. - Three pumps
We are filling the pool. The pool would fill the first pump in 12 hours and the second in 15 hours. If all three pumps ran simultaneously, they would fill the pool for 4 hours. How long would the pool fill only with the third pump? - The pool
The pool contains 220 m³ of water. Workers can empty the pool either: a) 10 hours of pipe B and 8 hours of pipe A, or b) 10 hours of pipe A and 7 hours of pipe B. How many cubic meters of water will flow in 1 hour from pipe A, and how many from pipe B? - Working together
One worker performs work in 3 days, the second in 5 days. How much do they work together?
- Water reservoir
One drain hole emptied the water from the tank for 20 hours, with the second drain for 30 hours. How long will the water drain from this tank if we open two drains simultaneously? - A report
Maricris can type a committee report in 5 hours. Jane helped Maricris, and together they finished the report in 3 hours. How long would it take Jane to complete the report she had worked on alone? - Right isosceles triangle
The right isosceles triangle has an altitude x drawn from the right angle to the hypotenuse dividing it into two equal segments. The length of one segment is 5 cm. What is the area of the triangle? - Minutes 7177
The tank holds 140 liters of water. The tank 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? - Summer tires
Three tire servants must change the summer tires on six cars in 2 hours. Mark's replacement would take 4.5 hours, Jirka would do it in 3 hours and 10 minutes, and Honza in 4 hours. Will they be able to replace all tires at the desired time?
- Evening shift
While working the evening shift, Officer K took 8 hours to complete a task at his workstation, and Officer M took 10 hours to complete the same task at his workstation. How many hours would it take Officer K and M to complete the same task, each working a - Two pumps
Pump A takes twice as long to fill a tank as B. Together, they take 2 hours to fill the tank. How long does each one take to fill the tank by itself? - Bricklayers
When a bricklayer works to redeem the house in 8 days, the other bricklayer will be finished in 10 days. How long will it take to make three such houses together? - Minute average
In a factory, four workers are assigned to complete an order received for dispatching 1400 boxes of a particular commodity. Worker A takes 4 minutes per box, Worker B takes 6 minutes per box, C takes 10 minutes per box, and D takes 15 minutes per box. Fin - Flying
The airplane from Prague to Bratislava was flying at a speed of 60 km/h less and back by 70 km/h greater than the original speed. What was the original speed if the plane returned to Prague according to the timetable?
- Together 5931
The tank will be filled with the first inlet in 5 hours and the second in 12 hours. How long would it take to fill the tank together? - Turners
Two turners perform joint work in 3 hours. The first-turner would perform the job himself in 7 hours. How long would the same job last for a second-turner if he worked alone? - In and out
The empty tank is filled in 12 minutes and empty in 16 minutes. How long does it take to fill if we forget to close the drain? The tank has 1000 liters of volume. - The pool
The pool has a volume of 40 m3, and the water temperature is 20 °C. How much water at 100 °C should we pour into the pool to increase the water temperature by 5 °C? - ICE train
German runways test a new ICE train between Munich and Berlin. The train runs to Berlin at a slow speed of 100 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
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Looking for calculator of harmonic mean? Harmonic mean - practice problems. Maths practice for 14 year olds.