The three painters have painted bridge. 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?
Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):
Showing 2 comments:
Why the third fraction 1/7.5 when it is supposed to be 1/7?
Yes, there was bug, but now is corrected. Thank you
To solve this example are needed these knowledge from mathematics:
Next similar examples:
An experienced soldier digs a good trench in 30 hours. Two soldiers dug the same trench each 40 hours. How many hours will the ditch dig all three together?
- Construction of road
For the construction of the road dam, it is supposed to transport six trucks a total of 18 days. After three days, two more cars were sent to the construction site. How long will it take to carry the material?
- Pumps A and B
Pump A fill the tank for 12 minutes, pump B for 24 minutes. How long will take to fill the tank if he is only three minutes works A and then both pumps A and B?
- Working together
One painter paint the nursery in 10 days, the second in 8 days. How many days will the nursery be painted if they work together?
- 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 workers fulfill a certain task when working together for 5 days, the first if he worked himself done work in 13 days. How many days will do whole job a second worker?
- Hectoliters of water
The pool has a total of 126 hectoliters of water. The first pump draws 2.1 liters of water per second. A second pump pumps 3.5 liters of water per second. How long will it take both pumps to drain four-fifths of the water at the same time?
- The factory
The factory z can complete an order in 12 days, factory p in 18 days. For how many days does an order completed when the first two days work only the factory z and then both factories?
- Evening shift
While working the evening shift, Officer K took 8 hours to complete a task at his work station and Officer M took 10 hours to complete the same task at his work station. How many hours would it take Officer K and Officer M to complete the same task working
- Mow the lawn
Dano would mow the lawn in 12 hours and Milada in 16 hours. How long will take the lawn mow together?
- Workers 9
If two workers fix two windows in an hour how many windows can 18 workers fix in the same two windows?
The tank is filled with a larger pump in 12 hours and with scond pump in 15 hours. For how long does the tank fill when both pumps are switched on at the same time?
Ondra digs the bed in 20 minutes. Cuba in 30 minutes. For how long do they dig together?
Two workers will construct the stage at the festival in 54 hours. Organizers need to shorten the assembly time by 42 hours. How many workers must the assembly company send?
- Two diggers
There are two diggers. One digger digs a pit 46 hours second gidding 2 times faster. a) how long took to dig a pit second digger b) how long took dig together
- Simplify 2
Simplify expression: 5ab-7+3ba-9
- Greg and Bill
Greg is 18 years old. He is 6 less than 4 times Bill's age. How old is Bill?