At a certain time of day a 6 ft man casts a 4ft shadow, at the same time day how tall is a tree that casts am 18ft shadow?

Esta piña es mi piña. correct incorrect

Am i correct on #2 spanish question above?

Which word best completes the sentence? isabela: no puedes permitir entrar ni vendedores perros callejeros. a. nunca b. ni c. siempre d. alguien