Harmonic mean + work - practice problems - page 4 of 6
Number of problems found: 110
- 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? - Three pumps
The water tank is emptied with the first pump in 6 hours, with the second pump in 2 hours. In order to be emptied in 1 hour, all three pumps had to be started at once. How long will it take to empty the tank by only the third pump? - Two brothers
Two brothers want to collect 20 kg of chestnuts. If only Marek collected, he would make it in 30 minutes. It would take Milan 10 minutes longer. How long after Mark does Milan have to start collecting to be finished in 18 minutes?
- Together 5931
The tank will be filled with the first inlet in 5 hours and the second in 12 hours. How long would it take to fill the tank together? - Turners
Two turners perform joint work in 3 hours. The first-turner would perform the job himself in 7 hours. How long would the same job last for a second-turner if he worked alone? - In and out
The empty tank is filled in 12 minutes and empty in 16 minutes. How long does it take to fill if we forget to close the drain? The tank has 1000 liters of volume. - Mow the lawn
Dano would mow the lawn in 12 hours and Milada in 16 hours. How long will it take the lawn mow together? - Pond
Workers will empty a pond with two open floodgates in 20 days. A larger floodgate will empty the whole pond in 30 days. For how long would he be emptied with a smaller floodgate?
- Pumping
The tank is filled with a larger pump in 12 hours and with a second pump in 15 hours. For how long does the tank fill when both pumps are switched on at the same time? - Oil tank and pipes
Two oil pipelines can fill the underground oil tank. The first is filled in 72 hours, and the second in 48 hours. How many hours from when the first pipeline began to fill the oil is necessary to start filling it with the second to fill in 1 and 1/2 days? - Pumps 4912
A pool with one pump fills in 14 hours and the other in 15 hours. How long will the pool fill when both pumps are used? - Two rooms
A woman cleans the room in 30 minutes, and a man in 90 minutes. How long will it take them clean two rooms? - Together 4511
One tractor would sow the field in 3 hours and the other in 7 hours. How long before the fields grow together?
- Completes 4234
The worker completes the work in 12 days, the second in 10 days. The first worker kicks himself for four days, then the second worker comes. How long will it take to dig? - Work together
Michal and Dorota would do the work together in 2.25 hours. If Dorota had to do it herself, it would have taken her 6 hours longer than Michal. Determine when Dorota would do the work herself and that Michal would do it himself. - Independently 3874
Josef would do the work himself in 5 hours. Josef and Michal would do the work together in 3.5 hours. Determine how long it would take Michal to do the job independently. - Determine 3851
Michal would cut the fence himself in 12 hours. It would take Michal and Juraj 8 hours together. Determine how long it would take for Juraj to do the job. - 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?
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