According to the given data we have the following proportion:
8hours/10 workers = Xhours/15 workers
A) The above proportion is not appropiate for solving the problem.
Since, the relationship between the number of workers and the time taken for sewing is an inverse relation:
The above proportion is just a direcly proportional relation.
B). As I stated above the relationship between the number of workers and the time taken for sewing is an inverse relation, hence, if the number of workers doubles then the number of time taken reduces to half.
So, since 15=10*15/10
therefore, time taken for 15 workers to sew pants is:
8/ 15/10 = 8* 10/15
=5 1/3 hours.
The time taken for 15 workers to sew pants is 5 1/3 hours.