Jenny washed fishes 4 times as many times as her brother last mont. her brother washed dishes 8 times. jenny said she could multiply 3 times 8 to find how many more times she washed dishes than her brother. is jenny correct? explain.

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.