Respuesta :
Most speakers would know what you meant. They both mean the same thing, . although the second one doesn't have the most proper grammar. but either one would work but the best option would be the first.
So for the first sentence "How many days would it take?" it is what most people would say rather that "How many days it would take?". Both sentences mean the same thing but the first sentence is proper rather than the second sentence.
Hope this helps you