Please help 5 points it pretty easy

"princess tower" in dubai is considered the world's tallest residential building, towering to 1 0 1 101 floors! t ( n ) t(n) models the number of tenants living on floor n n of the tower. what does the statement t ( 2 0 ) = t ( c ) t(20)=t(c) mean?

An arithmetic series a consists of consecutive integers that are multiples of 4 what is the sum of the first 9 terms of this sequence if the first term is 0

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