Just flew r miles in m hours and arrived 2 hours late how fast should she have flown to arrive on time

Answer 1

She flew r miles in m hours and was 2 hours late. We see that she flew at r/m mph. To be on time, she needs to fly in m-2 hours. She still needs to go r miles to get to her destination; we can't change that. So, if she flies at r/(m-2) mph, she will get there exactly on time.