Listen to the audio, read the question, and select the correct answer. how old is juan?

Can somebody me out with this spanish question? completa la oración con la voz pasiva con se. used cars for sale. carros usados. (the answer is not usa los or venta de)

Achemist mixes 4 liters of one acid solution with 10 liters of a 40% solution, resulting in a 30% acid solution. what is the value of x, the acid concentration of the first solution

Which word best completes the sentence? en los restaurantes de ecuador, la gente fumar en el exterior.a. necesario b. ni c. siempre d. debe