Respuesta :
In 12 days 15 men can do the work
In 1 day 12*15 men can do the work
In 6 days 12*15/6 men can do the work
so, in 6 days 30 men can do the work
In 12 days 15 men can do the work
In 1 day 12*15 men can do the work
In 6 days 12*15/6 men can do the work
so, in 6 days 30 men can do the work