Bob roller blades 9 miles each morning. today, he averaged 10 miles per hour for the first 6 miles but then slowed to 5 miles per hour for the rest of the trip. how long did the entire trip take?

The perimeter of ? cde is 55 cm. a rhombus dmfn is inscribed in this triangle so that vertices m, f, and n lie on the sides cd , ce , and de respectively. find cd and de if cf=8 cm and ef=12 cm. the answer is not cd=20 and de=15. i have tried that one, it does not work.