If z varies directly as x, and z =30when x=8,findz when x=4

Someone me i need with this stuff

In 2009, there were 1570 bears in a wildlife refuge. in 2010, the population had increased to approximately 1884 bears. if this trend continues and the bear population is increasing exponentially, how many bears will there be in 2018?

Which word in the sentence below is an interrogative pronoun? who is picking us up from school? whousisfrom