Harmonic mean - practice problems - page 6 of 10
The harmonic mean is a type of average that is particularly useful for calculating rates, ratios, or situations involving reciprocals.It is calculated as the reciprocal of the arithmetic mean of the reciprocals of a set of numbers.
The harmonic mean is often used when dealing with averages of quantities like speed, where time and distance are inversely related. It tends to be less affected by extremely large values in a dataset, making it more appropriate for skewed distributions compared to the arithmetic mean.
A key property of the harmonic mean is that it is always less than or equal to the arithmetic mean and the geometric mean for any set of positive numbers.
It is commonly applied in finance, such as calculating the average price-to-earnings ratio, and in physics, such as finding equivalent resistance in parallel circuits. The harmonic mean is not suitable for datasets containing zero or negative values, as it is undefined in such cases.
Number of problems found: 186
- 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 - Working together
One worker performs work in 3 days, the second in 5 days. How much do they work together? - Half-filled 7336
The water tank is filled with the first inflow in one hour and 10 minutes and the second in 60 minutes. How many minutes will the tank be half-filled with both inlets if the second outlet is opened 12 minutes later? - Calculation 7334
In a computer center, one computer would work 12 hours to solve a task, and another, more powerful, would solve the same task for 10.5 hours. If both computers work together, the calculation time would be reduced for a certain period. Calculate how long i
- The factory
The factory z can complete an order in 12 days, and factory p can complete it in 18 days. How many days does an order complete when the first two days work only the factory z and then both factories? - 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? - 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 - 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. One segment is 5 cm long. What is the area of the triangle?
- 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? - Soldier
An experienced soldier digs a good trench in 30 hours. Two soldiers dug the same trench every 40 hours. How many hours will the ditch dig all three together? - 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 long would it take Officer K and M to complete the same task, each working at his
- Together 3
If Sally can paint a house in 4 hours, and John can paint the same house in 6 hours, how long will it take for both of them to paint the house together?
- 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? - Performance
Two masons with the same performance would have been made of plaster for six days. One of them, however, has increased its daily performance by 50%. How long would it take them now to make plaster together? - 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 - Three painters The three painters have painted bridges. The first would work done in 5 days, the second in 6 days, and the third in 7.5 days. How long will the bridge work if they work together?
The water tank is emptied with the first pump in 6 hours and with the second pump in 2 hours. All three pumps had to be started at once to be emptied in 1 hour. How long will it take to empty the tank with only the third pump?Do you have homework that you need help solving? Ask a question, and we will try to solve it. Solving math problems.
