Rakesh delivered a slanderous speech

In the speech of a professor , the number of students present in the speech directly varies with his capacity of explaining the subjects abnd inversely with the number of speech delivered . If 54 students were present in 10 speeches of professor A , then what number of students will present in the speech delivered by B when the capacity of explanation of professor B is 3 times then that of A ?

Rakesh and Siva can do a piece of work in 15 days and 18 days respectively. They work together for 5 days and then Rakesh leaves. In how many days will Siva alone finish the remaining work?

Rakesh and Siva can do a piece of work in 15 days and 18 days respectively. They work together for 5 days and then Rakesh leaves. In how many days will Siva alone finish the remaining work?