Harmonic mean - practice for 12 year olds - last page
Number of problems found: 40
- Together 3781
Milos would do the work himself in 5 hours. How much would it take Dan to do the job together in two hours? - Two pumps
The first pump fills the tank in 24 hours second pump in another 40 hours. How long will it take to fill the tank if it operates both pumps simultaneously? - Three drivers
Three drivers driving in the same direction found that they have 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 - Tributaries
The first tributary fills the pool with water in 15 hours. The second tributary fills the pool in 10 hours. For how many hours is the pool filled with both tributaries?
- Boots
Master shoemaker has three apprentices. First, do one pair of boots for two days, second for one day, and third for 1.5 days. How long would it take to make a couple of boots if they worked together? - The dam
The water reservoir is filled with the first tributary for 25 hours second tributary for 35 hours. Some time was, both inlets open, then a second tributary closed, and they filled the tank in four hours. What time does water flow from both tributaries? (E - Grass garden
Mr. Grass would itself be mowed garden for 5 hours. His son Michael could do it for 7 hours. They agreed that they wake up at 5 am and begin to mow together. Ms. Grass needs to drive into town at 8.30. Michael says that at that time, they're done with wor - Two diggers
There are two diggers. One digger digs a pit 77 hours second, digging 1.2 times faster. a) how long took to dig a pit second digger b) how long took it to dig together - Pedestrian up-down hill
Pedestrian goes for a walk first at the plane at 4 km/h, then uphill at 3 km/h. Then it is in the middle of the route, turns back, and goes downhill at 6 km/h. The total walk was 6 hours. How many kilometers went pedestrians?
- Garden
Father dug up the garden in 11 few hours. Son in 15 hours. How many hours does it take to dig up the garden together? - Three workers
Three workers, A, B, and C, have to work on a specific task. Workers A and B completed the task in 12 days, B with C for 19 days, and A with C for 24 days. How long would it take to complete the task for everyone alone? How long would it take to complete - Blueberries
Marie earns 3 liters of blueberries for 3.4 hours, and Peter 2.4 liters for 2.9 hours. How long do they pick one liter together? - Machines
In the workshop are three machines. The first is treated 250 parts for 4.7 hours, the second is treated 300 parts for 1.9 hours, and the third is treated 230 parts for 4.6 hours. How long will it take to make 3100 parts if all three machines are worked si - Parquet floor
Three workers laid the parquet floor for 2.301 hour. The first would do this work alone 7 hours, the second in 6 hours. For how many hours would fulfill this work for the third worker if he worked alone?
- Inflow - outflow
The tank will fill by inflow for 56 minutes and empties by outflow for 77 minutes. How long does it take to fill the tank if it is also opened to the inflow and outflow? - Madams
During the spring cleaning, ladies were going to wash the windows. Mother takes to wash all the windows 5 hours, the grandmother takes 3 times longer, and Paula washes all windows in 2 hours. How many hours will you spend washing the windows of this "wome - Car
The car goes from point A to point B at speed 86 km/h and back 53 km/h. If it goes there and back at speed 67 km/h trip would take 10 minutes shorter. What is the distance between points A and B? - Tanker
The first pump can empty an oil tanker in 4.9 hour. The second pump can empty a tanker in 8 hours. If the first pump started at 4:00 and the second 1.4 hour later, at what time will the tanker be empty? - Steamship
Between the two ports on the river is going steamship. The journey there and back takes 8:42. Downstream steamship traveling at 20 km/h, upstream 9 km/h. What is the distance between the ports?
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Looking for calculator of harmonic mean? Harmonic mean - practice problems. Maths practice for 12-year-olds.