Harmonic mean - practice problems - page 5 of 11
Number of problems found: 208
- The leaves
Karel raked the leaves in the garden alone in 24 minutes, and his younger brother took 30 minutes. How long would they dig a garden if Karel digs alone for 6 minutes and his brother comes to his aid? - Worker trench time
Worker A will dig a trench in 12 days. Worker B will dig a trench in 18 days. How many days will it take them together? - Pool drainage calculation
During the pool cleaning, two drains and one inlet were opened. The first outflow would empty the pool in 6 hours, the second outflow would fill it in 9 hours, and the inflow would fill it in 12 hours. How long will it take to empty if the drains are open - Workshop order completion The plant has to complete the order in 40 working days. Production takes place in two workshops. In the first one, there are more workers; therefore, they would complete the order themselves in 70 working days. In the second workshop, they would complete
- Performance improvement percentage
How much percent performance improvement is needed if the work we have planned for five days has to be managed in three days? - Average speed
A car traveled from city A to city B at a speed of 40 km/h, then from B to C at 60 km/h, and finally from C to D at 50 km/h. Calculate the car's average speed over the entire route from A to D if the distance from A to B is 20% of the total distance and f - Reservoir pump filling
The reservoir is filled with the first pump in 30 hours, the second in 24 hours, and the third in 20 hours. How long does it take to fill the reservoir if all pumps are switched on simultaneously? - 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 - Panel house
The construction company has two groups of workers. Group A has more members than B. The Panel house was insulated by group A for ten days. They insulated the same block of flats together for 6 days. How many days would group B block insulate? - Birdhouse work time
Michal would make a birdhouse in three hours, and Richard would make it in two hours. If they work together, how many hours will it take them to complete it? How much percent more time compared to the time of working together would Michal make the booth b - Factory order completion
Factory A can fulfill the order independently in 10 days. Factory B fulfills the same order in 16 days. How many days will the order be completed if only plant B works on it for 3 days and then both plants together? - Mixture of nuts
We should prepare the mixture of nuts from almonds, peanuts, and nuts cashew ratio of 1:2:3 (respectively). The price of almonds is 150 CZK/kg, the price of peanuts is 140 CZK/kg, and the price of cashew nuts is 180 CZK/kg. The price of the mixture is det - Between two bus stops
Wanda lives between two bus stops at three-eighths of their distance. He started the house today and found that he would have arrived at the bus stop if he had run to one or the other. The average bus speed is 60 km/h. What is Wanda's average running spee - Average speed
The truck drove 1/2 of the way on the highway at 80 km/h. The other half of the way, 20 km/h. Calculate the average speed. - Two parts journey The driver of the car plans to drive 30 km in 0.5 hours. For 20 minutes he follows the convoy (traffic jam) at a speed of 30 km/h. What speed would he have to go in the remaining time?
- Motorcyclist average speed
The motorcyclist was riding: a) the first half of the driving time at a speed of 30 km/h, the second half of the time at a speed of 60 km/h, b) the track's first half at a speed of 30 km/h and the second half at a speed of 60 km/h. Determine its average s - Three altitudes
A triangle with altitudes 4, 5, and 6 cm is given. Calculate the lengths of all medians and all sides in a triangle. - Triangle height possibility
Is there a triangle with heights of 4, 7, and 10 meters? - Reading records
Lucy, Tereza, and Petra decided to compile the compulsory reading records together. It would take 30 days for Lucia alone, 36 for Tereza, and 45 for Petra. How long will it take to make records if they will work together?
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