Time + inverse relationship - examples
- Two workers
Two workers should fulfill certain task together for 5 days. If the first worker increased their performance twice and second twice fell, it took them just four days. For how many days would handle the entire task first worker himself?
If water flows into the pool by two inlets, fill the whole for 9 hours. First inlet filled pool 8 hour longer than second. How long pool is filled with two inlets separately?
- Forestry workers
In the forest is employed 63 laborers planting trees in nurseries. For 11 hour work day would end job in 43 days. After 14 days, 22 laborers go forth. How many days is needed to complete a planting trees in nurseries by others, if they will work 15 hours
Mr. Radoslav calculated that excavation for a water connection dig for 10 days. His friend would take 7 days. Radoslav worked 3 days alone. Then his friend came to help and started on the other end. On what day since the beginning of excavation they met?
Calculate fixed annual personnel costs of operating monorail line 106 km long if every 5 km is station, which serve three people - one dispatcher and two switchman in 3-shift operation. Consider the average salary of the employee 847 €.
- Road repair
Road repair took 16 days for 34 workers if they worked 6 hours a day. How many days take repair same road 33 workers if they work 6 per day?
Car goes from point A to point B at speed 70 km/h and back 76 km/h. If they goes there and back at speed 73 km/h trip would take 19 minutes shorter. What is distance between points A and B?
Two workers would make installation of greenhouses for 54 hours. For how many hours does the installation 9 workers?
- Train and car
The train and the car started at a constant speed to journey. When the train travels 78 km, the car travels 64 km. How many km travels the train when the car travels 78 km?
Workers A and B will done work together for 20 days. They worked together 18 days. Then A worker became ill and worker B finish the job alone for 11 days. If every worker was working alone, how many days took whole work for worker A and B?
- Painter Pavel
Painter Pavel painted the fence for 20 hours and painter Petr the same fence painted for 17 h. How long should take painted the fence together?
- Working time - shortening
The media often speculates about the change (especially to shorten) the working time of the five-day eight-hour working week to another working model. Calculate how many hours a day the employee would have to work a day at 6-day work week if he must work t
- Supermarket cashiers
When at the supermarket are opened only 2 cash people waiting in the front approximately 12 minutes. How many will shorten the average waiting time in a front where supermarket open another three cashiers?
- Forth and back
Car goes from point A to point B at speed 78 km/h and back at 82 km/h. If went there and back at speed 81 km/h journey would take five minutes less. What is the distance between points A and B?
- Hurry - rush
At an average speed 10 km/h I will come from the school to the bus stop for 29 minutes. How fast I need to go if I need to get to the bus stop in 21 minutes?
I embroider tablecloth in 20 days but if I embroider 3/4 hours a day I have embroider it for 15 days. How long do I embroider a day?
- Pumps 3
Two pumps of the same power fill the garden pool for 10 hours. How many of these pumps would have to use if we want to shorten the filling of the pool to four hours?
- Trrops - soldiers
Food stocks will last 20 soldiers of the 4-day training. How many days they could extend training if four soldiers become sick?
- Tank No 8
Tank is filled by one inlet valve with a flow rate of 12 liters per second in 72 minutes. How long take the tank to fill, if we open half an hour after one more inlet?
- Painting rooms
If Dano paint three hours daily given work he complete in 7.5 days. How many hours a day would have to work to finish the job 1.5 days earlier?