.
Use the proportion
= ,
where x is the unknown number of workers under the question.
The proportion says that the rate of work of each single worker is the same, measured in parts of the total job per hour per worker.
From the proportion, find x = = = 15*2 = 30 workers. ANSWER
By doing in this way, you have easy way to create an equation (a proportion) based on clear idea of the rate of work.
So, you will never make a mistake in this way.
-----------------
To see many other similar solved problems, look into the lesson
- Rate of work problems
in this site.