Three people

Three people start doing a work at a same time. The first worked only 2 hours. The second ended 3 hours before the end. On an individual basis, it would take the first time to do the work 10 hours, second 12 hours and 15 hours third. How many hours did it take to work together under these conditions?

Correct result:

t =  7 h

Solution:

2/10 + (t-3)/12 + t/15 = 1

9t = 63

t = 7

Our simple equation calculator calculates it.

Try another example

Showing 0 comments:

Next similar math problems:

• Working together
  Two people will do the work in 12 days. They worked together for 8 days. Then only one worked for 10 days. How many days would each of them do the work if he worked alone?
• Two workers
  The first worker completed the task by himself in 9 hours, the second in 15 hours. After two hours of joint work left first worker to a doctor and the second finished the job himself. How many hours worked second worker himself?
• Two tributaries
  Two tributaries of the pool fill it in 10 hours. One of the tributaries would fill 15 hours. How long would fill the first tributary?
• Tributaries
  The first tributary fill pool with water in 15 hours. The second tributary fill pool in 10 hours. For how many hours the pool is filled with both tributaries?
• Three painters
  One painter would have painted the fence for 15 hours, the second in 12 hours. The plot had to be painted in four hours, so they called the third one, and all worked together. For what time would the third painter paint fence the fence alone?
• Parquet floor
  Three workers laid parquet floor for 2.301 hour. The first one would do this work alone 7 hours, the second in 6 hours. For how many hours would fulfill this work the third worker, if he worked alone?
• Two friends
  Peter can do all his work himself in 6 hours. Martin can do the same work himself in 8 hours. Peter worked first and then replaced by Martin. Whole work was done in 6.5 hours. Calculate how long Peter worked before replaced by Martin.
• Two workers
  One worker needs 40 hours to do a job, and the second would do it in 30 hours. They worked together for several hours, then the second was recalled, and the first completed the job itself in 5 hours. How many hours did they work together, and how much did
• Hectares of forest
  12 workers plant 24 ha of forest in 6 days. In how many days will 15 people and 12 people plant the same area?
• Pool 2
  The first supply by the pool fill for five hours and the second fill for six hours, drain should be drained for 15 hours. For how many hours the pool is full, when we open both inlet now and outlet open two hours later?
• Workers 2
  Worker dug the trench for 7 hours, another worker for 10 hours. They recruited to work even one worker more. Digging should be done for 2 hours. For how long would dig third worker alone?
• Two workers
  The first worker would himself completed the work in 8 hours, the other in 6 hours. After two hours of joint work, the worker left the first worker to a doctor, and others completed the work himself. How many hours worked the other worker himself?
• Digging
  The first worker would dig a trench in 6 hours. For the second, the same work would take 4 hours. How long did it take for the trench to be dug if they worked together?
• Three tributaries
  It is possible to fill the pool with three tributaries. The first would take 12 hours, the second 15 hours, and the third 20 hours. The day before the summer season began, the manager opened all three tributaries simultaneously. How long did it take to fi
• Work
  The first worker would need less than 4 hours to complete the task than the other worker. In fact, both workers worked for two hours together, then the first worker did the remaining work himself. In what proportion should the remuneration of the workers
• Three pumps
  We are filling the pool. The first pump would be filled in 12 hours, the second pump in 15 hours. If all three pumps were running at the same time, it would fill the pool for 4 hours. How long would the pool fill only with the third pump?
• Harvesters
  The first harvester will harvest the grain from the field in 20 hours, the second, the more powerful in 10 hours. How long will take harvest this field by both harvesters, if the second harvester has to be set up first and this takes 2 hours? The first ha