Geometric series Homework (quick question) Pyramid with paper cups > 16 rows

Bottom row> 61 cups

Top row > 1 cup

How many cups in total?

I'm pretty sure this has to do with geometric series formula but I cant seem to get my head around it. explanation would be appreciated :)

The head librarian at the library of congress has asked her assistant for an interval estimate of the mean number of books checked out each day. the assistant provides the following interval estimate: from 740 to 920 books per day. what is an efficient, unbiased point estimate of the number of books checked out each day at the library of congress?

Solve the following simultaneous equation by using an algebraic method (either substitution or elimination) 2x + 3y=-4 4x-y=11

Let f(x) = 5/x and g(x)=2x2+5x. what two numbers are not in the domain of f o g