From the start till the catching up moment Nancy traveled 5*87 = 435 miles. Melanie traveled the same distance, and her way consisted of two parts: a) head -start distance, and b) 5*78 = 390 miles. Hence, Melanie's head-start was 435 - 390 = 45 miles. To cover this distance of 45 miles, Melanie took= of an hour =~ 0.5769 of an hour =~ 34.6 minutes.