A class of 90 students from civil, mechanical and electrical engineering backgrounds is divided into 2 sections (sections a and b). section a contains of 15 civil engineers and a total of 40 students. section b contains 20 mechanical engineers. there are a total 40 civil engineers and 30 mechanical engineers in the class. (a)what is the probability that a randomly selected student from section a is an electrical engineer? (b) what is the probability that a randomly selected student is a civil engineer and from section b?