Unwanted Pregnancy found. Last coitus?

My friend got pregnant, she just checked thrice yesterday on prega sure and all of the 3 were positive. She was suppose to get periods within these days even ut she dint. Also herself and her artner did intercourse on 1st of feb and 20th of feb but within 1st and 20th feb she dint felt anything weird at all.. Nothing was weird... Everything in her body was just  like other normal days. They both dont want to  have this child, as they are single and cant afford to have someone else and they are not ready for it. So they both are worried on what to do next and how to check that they are not late on checking this... As it could be possible that she got pregnant in the last coitus? Which was on 20th feb..?? Please help us on this.