Well, I'll answer your floor question first. You need to set a minimum price that you will charge for any job. What price makes you get off the couch and go to a home to clean it? For us, we have a $60 minimum and for us it QUICKLY goes up. If a job takes 25 minutes we need $60 to show up to do it. You must make your own minimum. Figure in drive time, gas, wear and tear on your vehicle and all the other things that it takes to get the job done.
Our answer if someone would have called us about only doing those floors would have been the same as any other phone call we receive. Can I get your name and address and a time for me to come look at it and give you a price?
Now you might be thinking.... but what if they say they just want a price and don't have time for me to come over. That's a lie... they have time. What you have is another cleaner wanting to know your prices. I don't know why other cleaners do this.... your business has nothing to do with their business. Anyway, my people are instructed to tell people if they don't have time for an estimate the price will be a minimum $750 and explain we have NO IDEA what we are getting in to so we must charge that to protect ourselves. At that point they are only wasting your time so the faster you get them off the phone the faster you can make money with a real customer.
Now to your first question. You know about how long it takes you to clean a house.... when you walk in to any house you can about tell how long you will be there. I can tell when I walk in how long a first time in will take and I can EASILY tell how long it will take on a regular basis (weekly/bi-weekly/4 weeks). Now that you have the time... how much do you charge per hour? Take those two number and multiply them and you have your answer.